In this paper, we report a study that examines the relationship between
image-based computational analyses of web pages and users' aesthetic judgments
about the same image material. Web pages were iteratively decomposed into
quadrants of minimum entropy (quadtree decomposition) based on low-level image
statistics, to permit a characterization of these pages in terms of their
respective organizational symmetry, balance and equilibrium. These attributes
were then evaluated for their correlation with human participants' subjective
ratings of the same web pages on four aesthetic and affective dimensions.
Several of these correlations were quite large and revealed interesting
patterns in the relationship between low-level (i.e., pixel-level) image
statistics and design-relevant dimensions.

We present an observational case study in which we investigate and analyze
the analytical processes of intelligence analysts. Participating analysts in
the study carry out two scenarios where they organize and triage information,
conduct intelligence analysis, report results, and collaborate with one
another. Through a combination of scenario-based analysis, artifact analysis,
role-playing, interviews, and participant observations, we explore the space
and boundaries in which intelligence analysts work and operate. We also assess
the implications of our findings on the use and application of key information
technologies.

An understanding of how people allocate their visual attention when viewing
Web pages is very important for Web authors, interface designers, advertisers
and others. Such knowledge opens the door to a variety of innovations, ranging
from improved Web page design to the creation of compact, yet recognizable,
visual representations of long pages. We present an eye-tracking study in which
20 users viewed 361 Web pages while engaged in information foraging and page
recognition tasks. From this data, we describe general location-based
characteristics of visual attention for Web pages dependent on different tasks
and demographics, and generate a model for predicting the visual attention that
individual page elements may receive. Finally, we introduce the concept of
fixation impact, a new method for mapping gaze data to visual scenes that is
motivated by findings in vision research.

Keywords: eye tracking, web design

Designing for other cultures

Designing digital games for rural children: a study of traditional village
games in India

Low educational levels hinder economic empowerment in developing countries.
We make the case that educational games can impact children in the developing
world. We report on exploratory studies with three communities in North and
South India to show some problems with digital games that fail to match rural
children's understanding of games, to highlight that there is much for us to
learn about designing games that are culturally meaningful to them. We describe
28 traditional village games that they play, based on our contextual
interviews. We analyze the mechanics in these games and compare these mechanics
against existing videogames to show what makes traditional games unique. Our
analysis has helped us to interpret the playability issues that we observed in
our exploratory studies, and informed the design of a new videogame that rural
children found to be more intuitive and engaging.

Keywords: developing world, digital divide, games, traditional games

Non-universal usability?: a survey of how usability is understood by Chinese
and Danish users

Most research assumes that usability is understood similarly by users in
different cultures, implying that the notion of usability, its aspects, and
their interrelations are constant across cultures. The present study shows that
this is not the case for a sample of 412 users from China and Denmark, who
differ in how they understand and prioritize different aspects of usability.
Chinese users appear to be more concerned with visual appearance, satisfaction,
and fun than Danish users; Danish users prioritize effectiveness, efficiency,
and lack of frustration higher than Chinese users. The results suggest that
culture influences perceptions of usability. We discuss implications for
usability research and for usability practice.

Keywords: culture, questionnaire, usability

A comparative study of speech and dialed input voice interfaces in rural
India

In this paper we present a study comparing speech and dialed input voice
user interfaces for farmers in Gujarat, India. We ran a controlled,
between-subjects experiment with 45 participants. We found that the task
completion rates were significantly higher with dialed input, particularly for
subjects under age 30 and those with less than an eighth grade education.
Additionally, participants using dialed input demonstrated a significantly
greater performance improvement from the first to final task, and reported less
difficulty providing input to the system.

Despite increased knowledge about how Information and Communications
Technologies (ICTs) are used to support religious and spiritual practices,
designers know little about how to design technologies for faith-related
purposes. Our research suggests incorporating sacred imagery into
techno-spiritual applications can be useful in guiding development. We
illustrate this through the design and evaluation of a mobile phone application
developed to support Islamic prayer practices. Our contribution is to show how
religious imagery can be used in the design of applications that go beyond the
provision of functionality to connect people to the experience of religion.

Keywords: HCI, design, mobile computing, spiritual computing

Expertise/people finding

Expert recommender systems (ERS) are considered a promising technology in
knowledge management. However, there are very few studies which evaluated their
appropriation in practice. In this paper, we present results of a case study of
expert recommender technology in a large European industrial association.
Unlike existing expert recommender approaches, the system involves users in
selecting textual documents for semi-automatic profile generation. Our study
focuses on the appropriation of this functionality and discusses impacts from
an organizational perspective.

Contemporary work increasingly involves interacting with strangers in
technology-mediated environments. In this context, we come to rely on digital
artifacts to infer characteristics of other people. This paper reports the
results of a study conducted in a global company that used expertise search as
a vehicle for exploring how people interpret a range of information available
in online profiles in evaluating whom to interact with for expertise. Using
signaling theory as a conceptual framework, we describe how certain 'signals'
in various social software are hard to fake, and are thus more reliable
indicators of expertise. Multi-level regression analysis revealed that
participation in social software, social connection information, and
self-described expertise in the corporate directory were significantly helpful
in the decision to contact someone for expertise. Qualitative analysis provided
further insights regarding the interpretations people form of others' expertise
from digital artifacts. We conclude with suggestions on differentiating various
types of information available within online profiles and implications for the
design of expertise locator/recommender systems.

Exercising is often a social activity performed with other people, yet
finding compatible exercise partners is difficult in practice. To gain a better
understanding of the social requirements involved with forming exercise groups,
we conducted a two-phased exploratory study involving an online web
questionnaire with 96 respondents and two focus groups. Our results highlight
various aspects of collaborating with exercise partners, but also indicate the
limited utility of currently available systems to support such collaborations.
We discuss implications for collaborative technologies supporting exercise
group formation.

Many medium and large companies maintain internal employee directories.
Unfortunately, most directories only allow the lookup of individual profiles,
one profile at a time. Team Analytics is a novel application that integrates
information from disparate enterprise tools for groups of people. Besides
accelerating the lookup process, Team Analytics also displays information that
is only available in the group context, such as an organizational chart and
time zone awareness. We present the Team Analytics application, its integration
with our corporate email client, and results from a user survey that evaluates
various aspects of the application.

Design methods

The use of examples serves a critical role in creative design practice, but
details of this process remain an enigma. This is problematic for both the
understanding of design activity as well as for developing more effective
design tools. In this paper, we report results of a study that understands and
compares how designers (N=11) utilize, manage, and share examples to support
the creative design process. The domains studied were Web, graphic, and product
design. Our study shows that examples are a cornerstone of creative practice
and are utilized for many reasons throughout the design process. Since examples
are pivotal to the success of a project, more effective tools that support
retrieval, storage, and dissemination of examples are needed. This paper
contributes understanding of the benefits and roles of examples in the design
process and implications for the design of more effective tools that support
example usage.

Group brainstorming is a popular ideation method for design teams, yet
brainstorming outcomes vary greatly. The method depends on individuals working
collectively to generate ideas, and so group dynamics determine whether the
method succeeds or fails. This paper explores how interaction designers used
techniques from theatrical improvisation, or improv, to adhere to the rules of
brainstorming thereby enhancing group interactions while collaborating. The
usefulness of improvisation for brainstorming stems from the similarity of the
goals of improvisation and brainstorming, the similarity of the recurrent
problems that actors and designers encounter when collaborating, and the
distinctness of the ways each have devised to resolve the problems that block
the group's performance. This paper reflects on the individual- and group-level
outcomes for design students and practitioners while brainstorming.

We propose a new perspective, seeing interactivity that is the immaterial
part of an interactive artifact as something concretely describable and
perceivable as we do with physical materials. In order to examine the validity
of this proposal, we extracted a set of interactivity attributes to be used as
a design language for thinking and describing interactivity in a new way, and
conducted an online survey with 14 Flash prototypes representing pairs of
values of 7 interactivity attributes we extracted. The result showed that all
the interactivity attributes were significant, and participants experienced
distinctive and meaningful emotional effects for different interactivity
attributes.

In this paper, we discuss some unique challenges of sustainable interaction
design (SID) and present our work that aims to reduce paper waste from web
printing. We conducted a two-month field study of current behaviors and
attitudes around printing, and the results confirmed the affordances of paper,
but also revealed many problems associated with printing web content. We then
designed and implemented a browser extension, PrintMarmoset, that targets these
problems while simultaneously addressing user needs and environmental
responsibility. It allows users to effortless select or remove web content for
printing. We have also incorporated a data sharing mechanism into our solution
to assist in the adoption of the tool and created visualizations to encourage
user reflection and exploration.

Navigation

Important drawbacks of map-based navigation applications for mobile phones
are their small screen size and that users have to associate the information
provided by the mobile phone with the real word. Therefore, we designed,
implemented and evaluated the Rotating Compass -- a novel public display for
pedestrian navigation. Here, a floor display continuously shows different
directions (in a clockwise order) and the mobile phone informs the user when
their desired direction is indicated. To inform the user, the mobile phone
vibrates in synchronization with the indicated direction. We report an outdoor
study that compares a conventional paper map, a navigation application running
on a mobile device, navigation information provided by a public display, and
the Rotating Compass. The results provide clear evidence of the advantages of
the new interaction technique when considering task completion time, context
switches, disorientation events, usability satisfaction, workload and
multi-user support.

This paper demonstrates how useful content can be generated as a by-product
of an enjoyable mobile multiplayer game. In EyeSpy, players tag geographic
locations with photos or text. By locating the places in which other players'
tags were created and 'confirming' them, players earn points for themselves and
verify the tags' locations. As a side effect of game-play, EyeSpy produces a
collection of recognisable and findable geographic details, in the form of
photographs and text tags, that can be repurposed to support navigation tasks.
Two user trials of the game successfully produced an archive of geo-located
photographs and tags, and in a follow-up experiment we compared performance in
a navigation task using photographs from the game, with geo-referenced photos
collected from the Flickr website. Our experiences with EyeSpy support
reflection upon the design challenges presented by 'human computation' and the
production of usable by-products through mobile game-play.

A common effect of aging is decline in spatial cognition. This is an issue
for all elders, but particularly for elder drivers. To address this driving
issue, we propose a novel concept of an in-vehicle navigation display system
that displays navigation information directly onto the vehicle's windshield,
superimposing it on the driver's view of the actual road. An evaluation of our
simulated version of this display shows that it results in a significant
reduction in navigation errors and distraction-related measures compared to a
typical in-car navigation display for elder drivers. These results help us
understand how context-sensitive information and a simulated augmented reality
representation can be combined to minimize the cognitive load in translating
between virtual/information spaces and the real world.

Digital pen systems, originally designed to digitize annotations made on
physical paper, are evolving to permit a wider variety of applications.
Although the type and quality of pen feedback (e.g., haptic, audio, and visual)
have a huge impact on advancing the digital pen technology, dynamic visual
feedback has yet to be fully investigated. In parallel, miniature projectors
are an emerging technology with the potential to enhance visual feedback for
small mobile computing devices. In this paper we present the PenLight system,
which is a testbed to explore the interaction design space and its accompanying
interaction techniques in a digital pen embedded with a spatially-aware
miniature projector. Using our prototype, that simulates a miniature projection
(via a standard video projector), we visually augment paper documents, giving
the user immediate access to additional information and computational tools. We
also show how virtual ink can be managed in single and multi-user environments
to aid collaboration and data management. User evaluation with professional
architects indicated promise of our proposed techniques and their potential
utility in the paper-intensive domain of architecture.

Previous studies have outlined the advantages of multi-resolution large-area
displays over their fixed-resolution counterparts, however the mobility of the
focus region has up until the present time received little attention. To study
this phenomenon further, we have developed a multi-resolution tabletop display
system with a steerable high resolution focus region to compare the performance
between steerable and fixed focus region systems under different working
scenarios. We have classified these scenarios according to region of interest
(ROI) with analogies to different eye movement types (fixed, saccadic, and
pursuit ROI). Empirical data gathered during the course of a multi-faceted user
study demonstrates that the steerable focus region system significantly
outperforms the fixed focus region system. The former is shown to provide
enhanced display manipulation and proves especially advantageous in cases where
the user must maintain spatial awareness of the display content as is the case
in which, within a single session, several regions of the display are to be
visited.

Tabletop systems are currently being focused on and many applications using
these systems are being developed. In such tabletop systems, how to recognize
real objects on the table is an essential and important issue. In existing
tabletop systems, 2-D markers have been often used. However, their
black-and-white pattern, which means nothing to humans, spoils the appearance
of the object. We developed transparent markers on a liquid crystal display
(LCD) tabletop system by using the polarization features of the LCD and optical
lms. In particular, through experiments with various kinds of optical films, we
found that two halfwave plates make the markers rotation invariant. By using
the transparent markers, tangible transparent Magic Lenses(TM) applications
were developed.

Robots

Typical Human Robot Interaction (HRI) assumes that the user explicitly
interacts with robots. However, explicit control with robots can be unnecessary
or even undesirable in certain cases, such as dealing with domestic services
(or housework). In this paper, we propose an alternative strategy of
interaction: the user implicitly controls a robot by issuing commands on
corresponding real world objects and the environment. Robots then discover
these commands and complete them in the background. We implemented a
paper-tag-based interface to support such implicit robot control in a
sensor-augmented home environment. Our initial user studies indicated that the
paper-tag-based interface is particularly simple to use and provides users with
flexibility in planning and controlling their housework tasks in a simulated
home environment.

We present a system whereby the human voice may specify continuous control
signals to manipulate a simulated 2D robotic arm and a real 3D robotic arm. Our
goal is to move towards making accessible the manipulation of everyday objects
to individuals with motor impairments. Using our system, we performed several
studies using control style variants for both the 2D and 3D arms. Results show
that it is indeed possible for a user to learn to effectively manipulate
real-world objects with a robotic arm using only non-verbal voice as a control
mechanism. Our results provide strong evidence that the further development of
non-verbal voice controlled robotics and prosthetic limbs will be successful.

We present a study of how householders personalize their domestic vacuuming
robot, iRobot's Roomba". In particular, we build on Blom and Monk's [3] theory
of personalization that argues that personalization does not only occur
naturally but can also be induced by design choices. In this study, we created
a personalization toolkit, which allowed people to customize their Roomba's
appearance and distributed it to 15 households. Our observations of these
households provide empirical support that personalization can facilitate
positive experiences with a Roomba, and having materials to hand can increase
the odds of customization. We conclude by discussing design implications for
personalization.

Numerous robots have been developed, and some of them are already being used
in homes, institutions, and workplaces. Despite the development of useful robot
functions, the focus so far has not been on user interfaces of robots. General
users of robots find it hard to understand what the robots are doing and what
kind of work they can do. This paper presents an interface for the commanding
home robots by using stroke gestures on a computer screen. This interface
allows the user to control robots and design their behaviors by sketching the
robot's behaviors and actions on a top-down view from ceiling cameras. To
convey a feeling of directly controlling the robots, our interface employs the
live camera view. In this study, we focused on a house-cleaning task that is
typical of home robots, and developed a sketch interface for designing
behaviors of vacuuming robots.

Online relationships

This paper studies people recommendations designed to help users find known,
offline contacts and discover new friends on social networking sites. We
evaluated four recommender algorithms in an enterprise social networking site
using a personalized survey of 500 users and a field study of 3,000 users. We
found all algorithms effective in expanding users' friend lists. Algorithms
based on social network information were able to produce better-received
recommendations and find more known contacts for users, while algorithms using
similarity of user-created content were stronger in discovering new friends. We
also collected qualitative feedback from our survey users and draw several
meaningful design implications.

Social media treats all users the same: trusted friend or total stranger,
with little or nothing in between. In reality, relationships fall everywhere
along this spectrum, a topic social science has investigated for decades under
the theme of tie strength. Our work bridges this gap between theory and
practice. In this paper, we present a predictive model that maps social media
data to tie strength. The model builds on a dataset of over 2,000 social media
ties and performs quite well, distinguishing between strong and weak ties with
over 85% accuracy. We complement these quantitative findings with interviews
that unpack the relationships we could not predict. The paper concludes by
illustrating how modeling tie strength can improve social media design
elements, including privacy controls, message routing, friend introductions and
information prioritization.

Receiving poor results from a personalized recommendation system is
frustrating. When users try to compensate by putting on a "different face" and
game the system, the results can be even more frustrating. This paper
investigates how to improve the user experience of such systems by: 1) adding
personal photos to increase self-awareness, and 2) providing recommendations
interspersed with personal questions. A 2x2 web experiment (N=56) within the
context of an online dating match recommendation system was used to assess
these two effects. Displaying a person's photo stabilized both response
strategies and liking of a recommender's poor suggestions. Additionally,
presenting all of the results together at the end was less frustrating than
spreading them out. These results demonstrate that simple interface design
decisions can have profound effects on user behaviors and attitudes with
personalized recommendation systems.

When an offence occurs, the victim and offender can overcome the harm done
through forgiveness. This paper demonstrates how forgiveness can be supported
in social system design. We first describe what forgiveness is, how it is
motivated and what benefits follow from forgiveness. Based on this theoretical
analysis, we propose five provisions to guide designers who want to encourage
reparation in social systems.

Keywords: emotions, forgiveness, online offences, reparation

Education and science

Computer Algebra Systems (CAS) provide sophisticated functionality to assist
with mathematical problem solving. Despite their widespread adoption, however,
little work in the HCI community has examined the extent to which these
computational tools support domain experts. In this paper, we report findings
from a qualitative study investigating the work practices and tools of nine
mathematicians in a research setting. Counter to our expectations, our data
suggests that computational tools play only a minor role in their workflow,
with the limited use of CAS owing primarily to four factors: (1) the need for
transparency in CAS's reasoning to explain computed results; (2) the problem of
rigidity and formality in CAS's input/output style dialogue; (3) the need for
2D input to support a wide range of annotations, diagrams, and in-place
manipulation of objects of interest; and (4) the need for collaboration,
particularly in early stages of problem solving. While grounded in the study of
mathematicians, these findings (particularly the first) have implications for
the design of computational systems intended to support complex problem
solving.

For over a century, citizen scientists have volunteered to collect huge
quantities of data for professional scientists to analyze. We designed
Pathfinder, an online environment that challenges this traditional division of
labor by providing tools for citizen scientists to collaboratively discuss and
analyze the data they collect. We evaluated Pathfinder in a sustainability and
commuting context using a mixed methods approach in both naturalistic and
experimental settings. Our results showed that citizen scientists preferred
Pathfinder to a standard wiki and were able to go beyond data collection and
engage in deeper discussion and analyses. We also found that citizen scientists
require special types of technological support because they generate original
research. This paper offers an early example of the mutually beneficial
relationship between HCI and citizen science.

The field of wearable computing and e-textiles has recently attracted much
interest from the research and general community. Recent developments in this
field raises the possibility of e-textile construction kits for hobbyists and
novices alike. The unique nature of wearable computing and e-textiles also
gives it a lot of potential as an educational computing topic, as it allows
students to exercise their creativity and imagination while learning about
computing and technology.
However, there are numerous difficulties involved in deploying existing
technology in an educational environment. Current state of the art technology
and techniques are not yet robust or reliable enough to stand up to the demands
of educational computing, and they require a high level of skill from the user.
In this paper, we present the TeeBoard, a constructive platform for e-textiles
and wearable computing that is designed specifically to "lower the floor" for
the integration of e-textiles into educational computing.

Personal information management

Activity-based computing represents an alternative to the dominant
application- and document-centric model at the foundation of most mainstream
desktop computing interfaces. In this paper, we present in-depth results from
an in situ, longitudinal study of an activity-based computing system, Giornata.
We detail the ways that the specific features of this system influenced the
everyday work experiences of a small cohort of knowledge workers. Our analysis
provides contributions at several levels of granularity-we provide concrete
design recommendations based on participants' reactions to the particular
features of the Giornata system and a discussion about how our findings can
provide insight about the broader understanding of knowledge work and activity
within HCI.

Users find it hard to delete unimportant personal information which often
results in cluttered workspaces. We present a full design cycle for GrayArea, a
novel interface that allows users to demote unimportant files by dragging them
to a gray area at the bottom of their file folders. Demotion is an intermediate
option between keeping and deleting. It combines the advantages of deletion
(unimportant files don't compete for attention) and keeping (files are
retrieved in their folder context). We developed the GrayArea working prototype
using thorough iterative design. We evaluated it by asking 96 participants to
'clean' two folders with, and without, GrayArea. Using GrayArea reduced folder
clutter by 13%. Further, 81% of participants found it easier to demote than
delete files, and most indicated they would use GrayArea if provided in their
operating systems. The results provide strong evidence for the demotion
principle suggested by the user-subjective approach.

Could people use tagging to manage day-to-day work in their personal
computing environment? Could tagging be sufficiently generic and lightweight to
support diverse ways of working and, perhaps, support new and efficient
practices for managing applications and accessing documents? We investigate
these issues by implementing the TAGtivity system that enables users to tag
resources in the context of their ongoing work. We deployed TAGtivity and
studied users' tagging practices in their actual work places over a three week
period. Our analysis of interviews and logs reveals that affordances of the
TAGtivity system supported users in a variety of information and activity
management tasks. These include new practices for managing emerging activities
and ephemeral information and accessing documents across application data
silos.

Clicking on buttons

We present a novel method called motion-pointing for selecting a set of
visual items such as push-buttons without actually pointing to them. Instead,
each potential target displays a rhythmically animated point we call the
driver. To select a specific item, the user only has to imitate the motion of
its driver using the input device. Once the motion has been recognized by the
system, the user can confirm the selection to trigger the action. We consider
cyclic motions on an elliptic trajectory with a specific period, and study the
most effective methods for real-time matching such a trajectory, as well as the
range of parameters a human can reliably reproduce. We then show how to
implement motion-pointing in real applications using an interaction technique
we call move-and-stroke. Finally, we measure the throughput and error rate of
move-and-stroke in a controlled experiment. We show that the selection time is
linearly proportional to the number of input bits conveyed up to 6 bits,
confirming that motion-pointing is a practical input method.

Physical buttons have the unique ability to provide low-attention and
vision-free interactions through their intuitive tactile clues. Unfortunately,
the physicality of these interfaces makes them static, limiting the number and
types of user interfaces they can support. On the other hand, touch screen
technologies provide the ultimate interface flexibility, but offer no inherent
tactile qualities. In this paper, we describe a technique that seeks to occupy
the space between these two extremes -- offering some of the flexibility of
touch screens, while retaining the beneficial tactile properties of physical
interfaces.
The outcome of our investigations is a visual display that contains
deformable areas, able to produce physical buttons and other interface
elements. These tactile features can be dynamically brought into and out of the
interface, and otherwise manipulated under program control. The surfaces we
describe provide the full dynamics of a visual display (through rear
projection) as well as allowing for multitouch input (though an infrared
lighting and camera setup behind the display). To illustrate the tactile
capabilities of the surfaces, we describe a number of variations we uncovered
in our exploration and prototyping. These go beyond simple on/off actuation and
can be combined to provide a range of different possible tactile expressions. A
preliminary user study indicates that our dynamic buttons perform much like
physical buttons in tactile search tasks.

The introduction of a new generation of attractive touch screen-based
devices raises many basic usability questions whose answers may influence
future design and market direction. With a set of current mobile devices, we
conducted three experiments focusing on one of the most basic interaction
actions on touch screens: the operation of soft buttons. Issues investigated in
this set of experiments include: a comparison of soft button and hard button
performance; the impact of audio and vibrato-tactile feedback; the impact of
different types of touch sensors on use, behavior, and performance; a
quantitative comparison of finger and stylus operation; and an assessment of
the impact of soft button sizes below the traditional 22 mm recommendation as
well as below finger width.

Privacy and trust

Many commerce websites post privacy policies to address Internet shoppers'
privacy concerns. However, few users read or understand them. Iconic privacy
indicators may make privacy policies more accessible and easier for users to
understand: in this paper, we examine whether the timing and placement of
online privacy indicators impact Internet users' browsing and purchasing
decisions. We conducted a laboratory study where we controlled the placement of
privacy information, the timing of its appearance, the privacy level of each
website, and the price and items being purchased. We found that the timing of
privacy information had a significant impact on how much of a premium users
were willing to pay for privacy. We also found that timing had less impact when
users were willing to examine multiple websites. Finally, we found that users
paid more attention to privacy indicators when purchasing privacy-sensitive
items than when purchasing items that raised minimal privacy concerns.

This paper examines a visual design element unique to situated, hot-spot
style, services: locativeness. This is the extent to which the media
representing a service relates to its immediate physical environment. This
paper explores the effect of locativeness on trust with two studies assessing
user attitudes in depth. The first is an implicit, or preconscious, test and
the second an explicit test based on voiced value judgments. To provide a
richer context, the second study contrasts locativeness with other traditional
aspects of design: branding and quality. The results indicate users have a
strong implicit association between locative images and trust, and that this is
partially reflected in their explicit choices. This is an important interface
aspect that designers should consider in order to create trustworthy situated
services.

Social computing systems are increasingly a part of people's social
environment. Inherent to such communities is the collection and sharing of
personal information, which in turn may raise concerns about privacy. In this
study, we extend prior research on internet privacy to address questions about
antecedents of privacy concerns in social computing communities, as well as the
impact of privacy concerns in such communities. The results indicate that
users' trust in other community members, and the community's information
sharing norms have a negative impact on community-specific privacy concerns. We
also find that community-specific privacy concerns not only lead users to adopt
more restrictive information sharing settings, but also reduce the amount of
information they share with the community. In addition, we find that
information sharing is impacted by network centrality and the tenure of the
user in the community. Implications of the study for research and practice are
discussed.

Accessibility/special needs

Music is a multi-dimensional experience informed by much more than hearing
alone, and is thus accessible to people of all hearing abilities. In this paper
we describe a prototype system designed to enrich the experience of music for
the deaf by enhancing sensory input of information via channels other than
in-air audio reception by the ear. The system has two main components-a
vibrating 'Haptic Chair' and a computer display of informative visual effects
that correspond to features of the music. The Haptic Chair provides sensory
input of vibrations via touch. This system was developed based on an initial
concept guided by information obtained from a background survey conducted with
deaf people from multi-ethnic backgrounds and feedback received from two
profoundly deaf musicians. A formal user study with 43 deaf participants
suggested that the prototype system enhances the musical experience of a deaf
person. All of the users preferred either the Haptic Chair alone (54%) or the
Haptic Chair with the visual display (46%). The prototype system, especially
the Haptic Chair was so enthusiastically received by our subjects that it is
possible this system might significantly change the way the deaf community
experiences music.

Keywords: assistive technology, deaf, haptic, music visualisation

Longitudinal study of people learning to use continuous voice-based cursor
control

We conducted a 2.5 week longitudinal study with five motor impaired (MI) and
four non-impaired (NMI) participants, in which they learned to use the Vocal
Joystick, a voice-based user interface control system. We found that the
participants were able to learn the mapping between the vowel sounds and
directions used by the Vocal Joystick, and showed marked improvement in their
target acquisition performance. At the end of the ten session period, the NMI
group reached the same level of performance as the previously measured "expert"
Vocal Joystick performance, and the MI group was able to reach 70% of that
level. Two of the MI participants were also able to approach the performance of
their preferred device, a touchpad. We report on a number of issues that can
inform the development of further enhancements in the realm of voice-driven
computer control.

Previous research shows that text entry by gaze using dwell time is slow,
about 5-10 words per minute (wpm). These results are based on experiments with
novices using a constant dwell time, typically between 450 and 1000 ms. We
conducted a longitudinal study to find out how fast novices learn to type by
gaze using an adjustable dwell time. Our results show that the text entry rate
increased from 6.9 wpm in the first session to 19.9 wpm in the tenth session.
Correspondingly, the dwell time decreased from an average of 876 ms to 282 ms,
and the error rates decreased from 1.28% to .36%. The achieved typing speed of
nearly 20 wpm is comparable with the result of 17.3 wpm achieved in an earlier,
similar study with Dasher.

Keywords: gaze input, gaze typing, longitudinal study, text entry

How well do visual verbs work in daily communication for young and old
adults?

In this paper we study how verbs are visually conveyed in daily
communication contexts for both young and old adults. Four visual modes are
compared: a single static image, a panel of four static images, an animation,
and a video clip. The results reveal age effects, as well as performance
differences introduced by lexical verb properties and visual cues. We also
suggest guidelines for visual verb creation.

Keywords: age effects, verb visualization, visual communication

Sustainability 1

In this paper we explore sustainability in interaction design by reframing
concepts of user identity and use in a domestic setting. Building on our own
work on everyday design and Blevis's Sustainable Interaction Design principles,
we present examples from an ethnographic study of families in their homes which
illustrate design-in-use: the creative and sustainable ways people appropriate
and adapt designed artifacts. We claim that adopting a conception of the user
as a creative everyday designer generates a new set of design principles that
promote sustainable interaction design.

Researchers are developing mobile sensing platforms to facilitate public
awareness of environmental conditions. However, turning such awareness into
practical community action and political change requires more than just
collecting and presenting data. To inform research on mobile environmental
sensing, we conducted design fieldwork with government, private, and public
interest stakeholders. In parallel, we built an environmental air quality
sensing system and deployed it on street sweeping vehicles in a major U.S.
city; this served as a research vehicle by grounding our interviews and
affording us status as environmental action researchers. In this paper, we
present a qualitative analysis of the landscape of environmental action,
focusing on insights that will help researchers frame meaningful technological
interventions.

Sustainable HCI is now a recognized area of human-computer interaction
drawing from a variety of disciplinary approaches, including the arts. How
might HCI researchers working on sustainability productively understand the
discourses and practices of ecologically engaged art as a means of enriching
their own activities? We argue that an understanding of both the history of
ecologically engaged art, and the art-historical and critical discourses
surrounding it, provide a fruitful entry-point into a more critically aware
sustainable HCI. We illustrate this through a consideration of frameworks from
the arts, looking specifically at how these frameworks act more as generative
devices than prescriptive recipes. Taking artistic influences seriously will
require a concomitant rethinking of sustainable HCI standpoints -- a
potentially useful exercise for HCI research in general.

Keywords: art, design, reflective HCI, sustainable HCI

Creating thought and self-improvement

Designing for the self: making products that help people become the person
they desire to be

Product attachment theory describes how people learn to love certain
possessions through a process of meaning making. It provides a rich and as yet
untapped source of inspiration for driving the practice of experience design.
However, there are currently no guidelines that describe how to apply this
theory in design practice. Taking a research through design approach, I made
many different products with the goal of helping people become the person they
desire to be through their product interactions. Then, in order to better
understand how the different design teams applied attachment theory, I created
a set of design patterns that document the application of product attachment
theory to the interaction design of each product. I clustered the patterns
based on similarities across the different artifacts, and this produced six
framing constructs, which work as specific perspectives designers can take when
applying product attachment theory in an experience design project.

In this paper, we propose design strategies for persuasive technologies that
help people who want to change their everyday behaviors. Our strategies use
theory and prior work to substantially extend a set of existing design goals.
Our extensions specifically account for social characteristics and other
tactics that should be supported by persuasive technologies that target
long-term discretionary use throughout everyday life. We used these strategies
to design and build a system that encourages people to lead a physically active
lifestyle. Results from two field studies of the system -- a three-week trial
and a three-month experiment -- have shown that the system was successful at
helping people maintain a more physically active lifestyle and validate the
usefulness of the strategies.

The HCI community often operates under the assumption that interactivity
enhances the user experience. In this study we are particularly interested in
whether interactivity enhances an artistic experience by either promoting or
constraining an audience's enjoyment and creative identity. The goal of the
study was to test two research questions in an experimental context: 1.) How
does interactive art impact user satisfaction, and 2.) How does interactive art
shape the self-concept of the user as creative? Participants interacted with
the system in the Interaction (34 pairs) or No Interaction (37 pairs)
condition. Findings reveal that perceptions of interactivity correlate with
user satisfaction, but do not influence user identity.

We present a qualitative study based on interviews with nine IKEA Hackers --
people who go online to share the process of repurposing IKEA products to
create personalized objects. Whether they were making a self-conscious artistic
statement or simply modifying a towel rack to fit in a small bathroom, IKEA
hackers illuminate an emergent practice that provides insights into
contemporary changes in creativity. We discuss the motivations for IKEA hacking
and explore the impact of information technology on do-it-yourself culture,
design, and HCI.

Keywords: DIY, Ikea, creative tools, design

Telepresence and online media

Video conferencing attempts to convey subtle cues of face-to-face
interaction (F2F), but it is generally believed to be less effective than F2F.
We argue that careful design based on an understanding of non-verbal
communication can mitigate these differences. In this paper, we study the
effects of video image framing in one-on-one meetings on empathy formation. We
alter the video image by framing the display such that, in one condition, only
the head is visible while, in the other condition, the entire upper body is
visible. We include a F2F control case. We used two measures of dyad empathy
and found a significant difference between head-only framing and both
upper-body framing and F2F, but no significant difference between upper-body
framing and F2F.
Based on these and earlier results, we present some design heuristics for
video conferencing systems. We revisit earlier negative experimental results on
video systems in the light of these new experiments. We conclude that for
systems that preserve both gaze and upper-body cues, there is no evidence of
deficit in communication effectiveness compared to face-to-face meetings.

Media space is a promising but still immature technology to connect
distributed sites. We developed a simple additional function that moved a
remote camera forward when a local user approached a display so that the
approach was amplified by a remote person's expanding image accompanied by
motion parallax. We conducted an experiment in which we observed that a movable
camera enhanced social telepresence, which is the feeling of facing a remote
person in the same room. Despite the camera's movement, subjects believed that
the camera did not move and a zoom-in function expanded the image.
Surprisingly, a zoom-in camera that expanded the image as the movable camera
did, however, was ineffective probably because of a lack of motion parallax.
Although we explained nothing about the camera, most subjects noticed that
their walking caused the view's expansion. If a remote person initiated the
camera's movement, social telepresence could not be enhanced.

The bias in the news media is an inherent flaw of the news production
process. The resulting bias often causes a sharp increase in political
polarization and in the cost of conflict on social issues such as Iraq war. It
is very difficult, if not impossible, for readers to have penetrating views on
realities against such bias. This paper presents NewsCube, a novel Internet
news service aiming at mitigating the effect of media bias. NewsCube
automatically creates and promptly provides readers with multiple classified
viewpoints on a news event of interest. As such, it effectively helps readers
understand a fact from a plural of viewpoints and formulate their own, more
balanced viewpoints. While media bias problem has been studied extensively in
communications and social sciences, our work is the first to develop a news
service as a solution and study its effect. We discuss the effect of the
service through various user studies.

Learning challenges

One hallmark difficulty of children with Autism Spectrum Disorder (ASD)
centers on communication and speech. Research into computer visualizations of
voice has been shown to influence conversational patterns and allow users to
reflect upon their speech. In this paper, we present the Spoken Impact Project
(SIP), an effort to examine the effect of audio and visual feedback on
vocalizations in low-functioning children with ASD by providing them with
additional means of understanding and exploring their voice. This research
spans over 12 months, including the creation of multiple software packages and
detailed analysis of more than 20 hours of experimental video. SIP demonstrates
the potential of computer generated audio and visual feedback to encourage
vocalizations of children with ASD.

The Internet has become a place of refuge for individuals with autism
spectrum disorders (ASD). In particular, weblogs are a popular option for
personal expression via the Internet. Perhaps this means of communication is
well suited to bypassing deficits in social interaction and communication that
characterize ASD. Using the Linguistic Inquiry and Word Count (LIWC)
dictionaries [10], we compared blogs of individuals with ASD to the writing of
neurotypical (NT) bloggers. We found that rates of word usage were nearly
identical in the two groups with one exception -- there was more variation in
the use of social words in ASD compared to NT blogs. This similarity in
language between ASD and NT authors suggests that communication deficits
routinely found in people with ASD may be due to the social context in which
their communication skills are tested, and that the affordances of asynchronous
computer-mediated communication may offer alternative means of testing and
expression.

Touch is fundamental to our emotional well-being. Medical science is
starting to understand and develop touch-based therapies for autism spectrum,
mood, anxiety and borderline disorders. Based on the most promising touch
therapy protocols, we are presenting the first devices that simulate touch
through haptic devices to bring relief and assist clinical therapy for mental
health. We present several haptic systems that enable medical professionals to
facilitate the collaboration between patients and doctors and potentially pave
the way for a new form of non-invasive treatment that could be adapted from use
in care-giving facilities to public use. We developed these prototypes working
closely with a team of mental health professionals.

Tangibles on tables

Multi-touch interactions are a promising means of control for interactive
tabletops. However, a lack of precision and tactile feedback makes multi-touch
controls a poor fit for tasks where precision and feedback are crucial. We
present an approach that offers precise control and tactile feedback for
tabletop systems through the integration of dynamically re-mappable physical
controllers with the multi-touch environment, and we demonstrate this approach
in our collaborative tabletop audio editing environment. An observational user
study demonstrates that our approach can provide needed precision and feedback,
while preserving the collaborative benefits of a shared direct-manipulation
surface. Our observations also suggest that direct touch and physical
controllers can offer complementary benefits, and that providing both allows
users to adjust their control strategy based on considerations including
precision, convenience, visibility, and user role.

Keywords: interactive tabletops, surface computing

SLAP widgets: bridging the gap between virtual and physical controls on
tabletops

We present Silicone iLluminated Active Peripherals (SLAP), a system of
tangible, translucent widgets for use on multitouch tabletops. SLAP Widgets are
cast from silicone or made of acrylic, and include sliders, knobs, keyboards,
and buttons. They add tactile feedback to multi-touch tables, improving input
accuracy. Using rear projection, SLAP Widgets can be relabeled dynamically,
providing inexpensive, battery-free, and untethered augmentations. Furthermore,
SLAP combines the flexibility of virtual objects with physical affordances. We
evaluate how SLAP Widgets influence the user experience on tabletops compared
to virtual controls. Empirical studies show that SLAPWidgets are easy to use
and outperform virtual controls significantly in terms of accuracy and overall
interaction time.

Interaction with a remote team of robots in real time is a difficult
human-robot interaction (HRI) problem exacerbated by the complications of
unpredictable real-world environments, with solutions often resorting to a
larger-than-desirable ratio of operators to robots. We present two innovative
interfaces that allow a single operator to interact with a group of remote
robots. Using a tabletop computer the user can configure and manipulate groups
of robots directly by either using their fingers (touch) or by manipulating a
set of physical toys (tangible user interfaces). We recruited participants to
partake in a user study that required them to interact with a small group of
remote robots in simple tasks, and present our findings as a set of design
considerations.

Computer mediated communication 1

Instant messaging (IM) is a common and popular way for co-workers, Friends,
and family to stay in touch, but its always-on properties can sometimes lead
people to feel overexposed or too readily available to others for conversation.
This, in turn, may lead people to deceive others about their actual status or
availability. In this paper, we introduce the notion of the "butler lie to
describe lies that allow for polite initiation and termination of
conversations. We present results from a field study of 50 IM users, in which
participants rated each of their messages at the time of sending to indicate
whether or not it was deceptive. About one tenth of all IM messages were rated
as lies and, of these, about one fifth were butler lies. These results suggest
that butler lies are an important social practice in IM, and that existing
approaches to interpersonal awareness, which focus on accurate assessment of
availability, may need to take deception and other social practices into
account.

While most collaboration technologies are concerned with supporting
particular tasks such as workflows or meetings, many work groups do not have
the teamwork skills essential to effective collaboration. One way to improve
teamwork is to provide dynamic feedback generated by automated analyses of
behavior, such as language use. Such feedback can lead members to reflect on
and subsequently improve their collaborative behavior, but might also distract
from the task at hand. We have experimented with GroupMeter -- a chat-based
system that presents visual feedback on team members' language use. Feedback on
proportion of agreement words and overall word count was presented using two
different designs. When receiving feedback, teams in our study expressed more
agreement in their conversations and reported greater focus on language use as
compared to when not receiving feedback. This suggests that automated,
real-time linguistic feedback can elicit behavioral changes, offering
opportunities for future research.

Non-traditional interaction techniques

Modern presentation software is still built around interaction metaphors
adapted from traditional slide projectors. We provide an analysis of the
problems in this application genre that presentation authors face and present
Fly, a presentation tool that is based on the idea of planar information
structures. Inspired by the natural human thought processes of data chunking,
association, and spatial memory, Fly explores authoring of presentation
documents.
Evaluation of a paper prototype showed that the planar UI is easily grasped
by users, and leads to presentations more closely resembling the information
structure of the original content, thus providing better authoring support than
the slide metaphor. Our software prototype confirmed these results, and
outperformed PowerPoint in a second study for tasks such as prototyping
presentations and generating meaningful overviews. Users reported that this
interface helped them better to express their concepts, and expressed
significant preference for Fly over the traditional slide model.

We present results from an experiment examining the area occluded by the
hand when using a tablet-sized direct pen input device. Our results show that
the pen, hand, and forearm can occlude up to 47% of a 12 inch display. The
shape of the occluded area varies between participants due to differences in
pen grip rather than simply anatomical differences. For the most part,
individuals adopt a consistent posture for long and short selection tasks.
Overall, many occluded pixels are located higher relative to the pen than
previously thought. From the experimental data, a five-parameter scalable
circle and pivoting rectangle geometric model is presented which captures the
general shape of the occluded area relative to the pen position. This model
fits the experimental data much better than the simple bounding box model often
used implicitly by designers. The space of fitted parameters also serves to
quantify the shape of occlusion. Finally, an initial design for a predictive
version of the model is discussed.

Keywords: hand occlusion, pen input, tablet pc

Text entry performance of state of the art unconstrained handwriting
recognition: a longitudinal user study

We report on a longitudinal study of unconstrained handwriting recognition
performance. After 250 minutes of practice, participants had a mean text entry
rate of 24.1 wpm. For the first four hours of usage, entry and error rates of
handwriting recognition are about the same as for a baseline QWERTY software
keyboard. Our results reveal that unconstrained handwriting is faster than what
was previously assumed in the text entry literature.

We introduce a technique for exploring multi-layered images by scraping
arbitrary areas to determine meaningful relationships. Our system, called
Wetpaint, uses perceptual depth cues to help users intuitively navigate between
corresponding layers of an image, allowing a rapid assessment of changes and
relationships between different views of the same area. Inspired by art
diagnostic techniques, this tactile method could have distinct advantages in
the general domain as shown by our user study. We propose that the physical
metaphor of scraping facilitates the process of determining correlations
between layers of an image because it compresses the process of planning,
comparison and annotation into a single gesture. We discuss applications for
geography, design, and medicine.

In the living room

In this paper we explore the use of computer at home. This work is based on
the automatic recording of application focus data in natural situation from a
wide representative panel of 661 households with 1,434 users at home over 19
months. To process these large-scale data, we build a two-level classification
of PC applications describing the whole PC use. At the household level, we
worked on computer usage temporality: we observed two strategies of PC usage
reflecting a tension between synchronous and asynchronous usage profiles. At
the individual level, we found out that software preferences and usage
intensity are rather independent; therefore, we distinguished five specific
profiles of users reflecting strong routine behaviors of computer usage at
home. These observations tend to show the strength of routine behaviors in
computer usage.

Social television applications have emerged as a potentially valuable
convergence of media and communication, but questions remain about the utility
and nature of the communication experiences they will provide. We present our
study of STV3, an application that adds freeform text and voice chat
capabilities to the conventional television-viewing experience. We conducted an
in-depth field study of STV3 to understand how friends integrate communication
through social television into their lives. Our results reveal users' choices
of communication modality, their topics of conversation, and the sense of
connectedness that was fostered through their use of STV3. Our findings
indicate that participants overwhelmingly preferred text chat to voice chat,
and that they often communicated about topics unrelated to the television
content.

Keywords: cmc, communication, field studies, interactive television, social television

Supporting the social uses of television: sociability heuristics for social
tv

Various social television systems and applications, enabling remote
communication and interaction between viewers, are currently in development.
Although usability guidelines exist for interactive television to ensure a
usable system, there are no sociability guidelines for designing or evaluating
the social interaction these systems enable. In this paper we present twelve
sociability heuristics for evaluating social TV, based on several user studies
with social TV systems.

Keywords: evaluation, heuristics, sociability, social television

Information foraging

User interfaces and information systems have become increasingly social in
recent years, aimed at supporting the decentralized, cooperative production and
use of content. A theory that predicts the impact of interface and interaction
designs on such factors as participation rates and knowledge discovery is
likely to be useful. This paper reviews a variety of observed phenomena in
social information foraging and sketches a framework extending Information
Foraging Theory towards making predictions about the effects of diversity,
interference, and cost-of-effort on performance time, participation rates, and
utility of discoveries.

Keywords: social information foraging theory

Remembrance of things tagged: how tagging effort affects tag production and
human memory

We developed a low-effort interaction method called Click2Tag for social
bookmarking. Information foraging theory predicts that the production of tags
will increase as the effort required to do so is lowered, while the amount of
time invested decreases. However, models of human memory suggest that changes
in the tagging process may affect subsequent human memory for the tagged
material. We compared (1) low-effort tagging by mouse-clicking (Click2Tag), (2)
traditional tagging by typing (type-to-tag), and (3) baseline, no tagging
conditions. Our results suggest that (a) Click2Tag increases tagging rates, (b)
Click2Tag improves recognition of facts from the tagged text when compared to
type-to-tag, and (c) Click2Tag is comparable to the no-tagging baseline
condition on recall measures. Results suggest that tagging by clicking
strengthens the memory traces by repeated readings of relevant words in the
text and, thus, improves recognition.

Social tagging arose out of the need to organize found content that is worth
revisiting. A significant side effect has been the use of social tagging sites
as navigational signposts for interesting content. The collective behavior of
users who tagged contents seems to offer a good basis for exploratory search
interfaces, even for users who are not using social bookmarking sites. In this
paper, we present the design of a tag-based exploratory system and detail an
experiment in understanding its effectiveness. The tag-based search system
allows users to utilize relevance feedback on tags to indicate their interest
in various topics, enabling rapid exploration of the topic space. The
experiment shows that the system seems to provide a kind of scaffold for users
to learn new topics.

When gathering feedback about an envisioned system, prototypes communicate
design ideas to user groups. However, it is unclear how user responses are
affected by prototype format. We conducted a 2x2 quasi-experiment (video
/storyboard format x older and younger user groups) to test for an interaction
between prototype format and user group. We found a significant interaction
between prototype format and responses across user groups. Our results indicate
that differences in user responses can be misinterpreted as the result of user
group characteristics. We advise using multiple prototype formats to counteract
a 'media effect'. Alternatively, we advise using storyboards for a smaller
'media effect'.

Understanding UI 1

In this paper we argue against averaging as a common practice in the
analysis of subjective attribute judgments, both across and within subjects.
Previous work has raised awareness of the diversity between individuals'
perceptions. In this paper it will furthermore become apparent that such
diversity can also exist within a single individual, in the sense that
different attribute judgments from a subject may reveal different,
complementary, views. A Multi-Dimensional Scaling approach that accounts for
the diverse views on a set of stimuli is proposed and its added value is
illustrated using published data. We will illustrate that the averaging
analysis provides insight to only 1/6th of the total number of attributes in
the example dataset. The proposed approach accounts for more than double the
information obtained from the average model, and provides richer and
semantically diverse views on the set of stimuli.

Metrics

It is well-accepted that learnability is an important aspect of usability,
yet there is little agreement as to how learnability should be defined,
measured, and evaluated. In this paper, we present a survey of the previous
definitions, metrics, and evaluation methodologies which have been used for
software learnability. Our survey of evaluation methodologies leads us to a new
question-suggestion protocol, which, in a user study, was shown to expose a
significantly higher number of learnability issues in comparison to a more
traditional think-aloud protocol. Based on the issues identified in our study,
we present a classification system of learnability issues, and demonstrate how
these categories can lead to guidelines for addressing the associated
challenges.

One approach to reducing the costs of usability testing is to facilitate the
automatic detection of critical incidents: serious breakdowns in interaction
that stand out during software use. This research evaluates the use of undo and
erase events as indicators of critical incidents in Google SketchUp (a
3D-modeling application), measuring an indicator's usefulness by the numbers
and types of usability problems discovered. We compared problems identified
using undo and erase events to problems identified using the user-reported
critical incident technique [Hartson and Castillo 1998]. In a within-subjects
experiment with 35 participants, undo and erase episodes together revealed over
90% of the problems rated as severe, several of which would not have been
discovered by self-report alone. Moreover, problems found by all three methods
were rated as significantly more severe than those identified by only a subset
of methods. These results suggest that undo and erase events will serve as
useful complements to user-reported critical incidents for low cost usability
evaluation of creation-oriented applications like SketchUp.

Cross culture CMC

Supporting creativity via collaborative group brainstorming is a prevalent
practice in organizations. Today's technology makes it easy for international
and intercultural group members to brainstorm together remotely, but
surprisingly little is known about how culture and medium shape the underlying
brainstorming process. In a laboratory study, we examined the influences of
individual cultural background (American versus Chinese), group cultural
composition (same- versus mixed-culture groups), and communication medium
(text-only versus video-enabled chatrooms) on group brainstorming
conversations. Cultural differences and adaptation in conversational
talkativeness and responsiveness were identified. The text-only medium reduced
cultural differences in talkativeness. Working in a mixed-culture group led to
cultural adaptation in the communication style of Chinese but not American
participants. We discuss implications for international group brainstorming.

When people communicate in their native languages using machine translation,
they face various problems in constructing common ground. This study
investigates the difficulties of constructing common ground when multiparty
groups (consisting of more than two language communities) communicate using
machine translation. We compose triads whose members come from three different
language communities -- China, Korea, and Japan -- and compare their
referential communication under two conditions: in their shared second language
(English) and in their native languages using machine translation.
Consequently, our study suggests the importance of not only grounding between
speaker and addressee but also grounding between addressees in constructing
effective machine-translation-mediated communication. Furthermore, to
successfully build common ground between addressees, it seems important for
them to be able to monitor what is going on between a speaker and other
addressees.

Citizen response to disaster has begun to receive attention in the CHI
community but little attention has so far been given to how citizens use
technology to adapt when their country is at war. We report on an ethnographic
interview study of how technology was adopted and used by citizens to be
resilient during wartime. We interviewed 45 Iraqi citizens experiencing the
current Iraq war. Based on our data we identified properties of resilience:
reconfiguring social networks, self-organization, redundancy, proactive
practices, and repairing trust in information. Technology supported people in
being resilient by enabling them to control identity, to collaborate in travel,
to create an organizational memory, and to provide alternative sources of news
and information. As people adopted and used technology to be resilient we found
a merging of old and new cultural practices. We discuss these systemic changes
and describe implications for how technology can support people in being
resilient in disrupted environments.

Scientometric analysis of the CHI proceedings

The CHI conference has grown rapidly over the last 26 years. We present a
quantitative analysis on the countries and organizations that contribute to its
success. Only 7.8 percent of the countries are responsible for 80 percent of
the papers in the CHI proceedings, and the USA is clearly the country with most
papers. But the success of a country or organization does not depend only on
the number of accepted papers, but also on their quality. We present a ranking
of countries and organizations based on the h index, an indicator that tries to
balance the quantity and quality of scientific output based on a bibliometric
analysis. The bibliometric analysis also allowed us to demonstrate the
difficulty of judging quality. The papers acknowledged by the best paper award
committee were not cited more often than a random sample of papers from the
same years. The merit of the award is therefore unclear, and it might be
worthwhile to allow the visitor to the conference to vote for the best paper.

Keywords: bibliometrics, chi, g index, h index, history, quality

User experience

From interaction to trajectories: designing coherent journeys through user
experiences

The idea of interactional trajectories through interfaces has emerged as a
sensitizing concept from recent studies of tangible interfaces and interaction
in museums and galleries. We put this concept to work as a lens to reflect on
published studies of complex user experiences that extend over space and time
and involve multiple roles and interfaces. We develop a conceptual framework in
which trajectories explain these user experiences as journeys through hybrid
structures, punctuated by transitions, and in which interactivity and
collaboration are orchestrated. Our framework is intended to sensitize future
studies, help distill craft knowledge into design guidelines and patterns,
identify technology requirements, and provide a boundary object to connect HCI
with Performance Studies.

Despite the growing interest in user experience (UX), it has been hard to
gain a common agreement on the nature and scope of UX. In this paper, we report
a survey that gathered the views on UX of 275 researchers and practitioners
from academia and industry. Most respondents agree that UX is dynamic,
context-dependent, and subjective. With respect to the more controversial
issues, the authors propose to delineate UX as something individual (instead of
social) that emerges from interacting with a product, system, service or an
object. The draft ISO definition on UX seems to be in line with the survey
findings, although the issues of experiencing anticipated use and the object of
UX will require further explication. The outcome of this survey lays ground for
understanding, scoping, and defining the concept of user experience.

A recent trend in Human-Computer Interaction (HCI) research addresses human
needs that go beyond the instrumental, resulting in an increasing body of
knowledge about how users form overall evaluative judgments on the quality of
interactive products. An aspect largely neglected so far is that of
temporality, i.e. how the quality of users' experience develops over time. This
paper presents an in-depth, five-week ethnographic study that followed 6
individuals during an actual purchase of the Apple iPhone". We found prolonged
use to be motivated by different qualities than the ones that provided positive
initial experiences. Overall, while early experiences seemed to relate mostly
to hedonic aspects of product use, prolonged experiences became increasingly
more tied to aspects reflecting how the product becomes meaningful in one's
life. Based on the findings, we promote three directions for CHI practice:
designing for meaningful mediation, designing for daily rituals, and designing
for the self.

In the home

Prior research suggests that people may ask their family and friends for
computer help. But what influences whether and how a "helper" will provide
help? To answer this question, we conducted a qualitative investigation of
people who participated in computer support activities with family and friends
in the past year. We describe how factors including maintenance of one's
personal identity as a computer expert and accountability to one's social
network determine who receives help and the quality of help provided. We also
discuss the complex, fractured relationship between the numerous stakeholders
involved in the upkeep of home computing infrastructures. Based on our
findings, we provide implications for the design of systems to support informal
help-giving in residential settings.

We present results from a study examining how American Protestant
Christians' faith affects their domestic life. There are two contributions of
this work for the HCI community. First, we provide empirical evidence
demonstrating how topics of interest to HCI researchers (e.g., material
artifacts, routines, and ICT use) are used for religious purposes. Our findings
show how Christians distinguish these aspects of domestic life from their
secular counterparts. Second, we use our findings to reflect on current
directions of future domestic ICT applications. Specifically, we critically
evaluate the "problem solving approaches dominating the design of future
technologies, and present extraordinary computing or systems that promote and
honor the special value accorded to some aspects of domestic life.

Keywords: domestic technologies, religion

Q&A systems

Facts or friends?: distinguishing informational and conversational questions
in social Q&A sites

Tens of thousands of questions are asked and answered every day on social
question and answer (Q&A) Web sites such as Yahoo Answers. While these sites
generate an enormous volume of searchable data, the problem of determining
which questions and answers are archival quality has grown. One major component
of this problem is the prevalence of conversational questions, identified both
by Q&A sites and academic literature as questions that are intended simply to
start discussion. For example, a conversational question such as "do you
believe in evolution?" might successfully engage users in discussion, but
probably will not yield a useful web page for users searching for information
about evolution. Using data from three popular Q&A sites, we confirm that
humans can reliably distinguish between these conversational questions and
other informational questions, and present evidence that conversational
questions typically have much lower potential archival value than informational
questions. Further, we explore the use of machine learning techniques to
automatically classify questions as conversational or informational, learning
in the process about categorical, linguistic, and social differences between
different question types. Our algorithms approach human performance, attaining
89.7% classification accuracy in our experiments.

Community-based question and answer (Q&A) systems facilitate information
exchange and enable the creation of reusable knowledge repositories. While
these systems are growing in usage and are changing how people find and share
information, current designs are inefficient, wasting the time and attention of
their users. Furthermore, existing systems do not support signaling and
screening of joking and non-serious questions. Coupling Q&A services with
instant and text messaging for faster questions and answers may exacerbate
these issues, causing Q&A services to incur high interruption costs on their
users.
In this paper we present the design and evaluation of a market-based
real-time Q&A system. We compared its use to a similar Q&A system without a
market. We found that while markets can reduce wasted resources by reducing the
number of less important questions and low quality answers, it may also reduce
the socially conducive questions and usages that are vital to sustaining a Q&A
community.

Large general-purposed community question-answering sites are becoming
popular as a new venue for generating knowledge and helping users in their
information needs. In this paper we analyze the characteristics of knowledge
generation and user participation behavior in the largest question-answering
online community in South Korea, Naver Knowledge-iN. We collected and analyzed
over 2.6 million question/answer pairs from fifteen categories between 2002 and
2007, and have interviewed twenty six users to gain insights into their
motivations, roles, usage and expertise. We find altruism, learning, and
competency are frequent motivations for top answerers to participate, but that
participation is often highly intermittent. Using a simple measure of user
performance, we find that higher levels of participation correlate with better
performance. We also observe that users are motivated in part through a point
system to build a comprehensive knowledge database. These and other insights
have significant implications for future knowledge generating online
communities.

Keywords: online community, question-answering

Looking at videos

In this paper we propose a new video interaction model called adaptive
fast-forwarding to help people quickly browse videos with predefined semantic
rules. This model is designed around the metaphor of scenic car driving, in
which the driver slows down near areas of interest and speeds through
unexciting areas. Results from a preliminary user study of our video player
suggest the following: (1) the player should adaptively adjust the current
playback speed based on the complexity of the present scene and predefined
semantic events; (2) the player should learn user preferences about predefined
event types as well as a suitable playback speed; (3) the player should
fast-forward the video continuously with a playback rate acceptable to the user
to avoid missing any undefined events or areas of interest. Furthermore, our
user study results suggest that for certain types of video, our SmartPlayer
yields better user experiences in browsing and fast-forwarding videos than
existing video players' interaction models.

Tools to aid people in making sense of the information quality of online
informational video are essential for media consumers seeking to be well
informed. Our application, Videolyzer, addresses the information quality
problem in video by allowing politically motivated bloggers or journalists to
analyze, collect, and share criticisms of the information quality of online
political videos. Our interface innovates by providing a fine-grained and
tightly coupled interaction paradigm between the timeline, the time-synced
transcript, and annotations. We also incorporate automatic textual and video
content analysis to suggest areas of interest for further assessment by a
person. We present an evaluation of Videolyzer looking at the user experience,
usefulness, and behavior around the novel features of the UI as well as report
on the collaborative dynamic of the discourse generated with the tool.

In the world of visual storytelling, narrative development relies on a
particular temporal ordering of shots and sequences and scenes. Rarely is this
ordering cast in stone. Rather, the particular ordering of a story reflects a
myriad of interdependent decisions about the interplay of structure, narrative
arc and character development. For storytellers, particularly those developing
their narratives from large documentary archives, it would be helpful to have a
visualization system partnered with them to present suggestions for the most
compelling story path.
We present Storied Navigation, a video editing system that helps authors
compose a sequence of scenes that tell a story, by selecting from a corpus of
annotated clips. The clips are annotated in unrestricted natural language.
Authors can also type a story in unrestricted English, and the system finds
possibilities for clips that best match high-level elements of the story.
Beyond simple keyword matching, these elements can include the characters,
emotions, themes, and story structure. Authors can also interactively replace
existing scenes or predict the next scene to continue a story, based on these
characteristics. Storied Navigation gives the author the feel of brainstorming
about the story rather than simply editing the media.

Art creation

We focus on the creative use of paper in the music composition process,
particularly the interaction between paper and end-user programming. When
expressing musical ideas, composers draw in a precise way, not just sketch.
Working in close collaboration with composers, we designed Musink to provide
them with a smooth transition between paper drawings and OpenMusic, a flexible
music composition tool. Musink's built-in recognizers handle common needs, such
as scoping and annotation. Users can also define new gestures and associate
them with their own or predefined software functions. Musink supports
semi-structured, delayed interpretation and serves as a customizable gesture
browser, giving composers significant freedom to create their own,
individualized composition languages and to experiment with music, on-paper and
on-line.

This paper aims to contribute with an understanding of meaningful
experiences of photography, to support reflection upon the design of future
camera devices. We have conducted a study of a passive camera device called
Sensecam, which previously has been investigated as a memory aid, a combination
of life-logging and memory tool and as a resource for digital narratives. We
take a creative perspective and show that even if a camera is designed to be
forgotten in use (i.e. is worn as a necklace and takes pictures automatically)
it can still be part of an engaging or active photographic experience. Because
Sensecam is different from film cameras, camera phones and other digital
cameras, it involves a different type of photographic experience, for example
when moving through different social contexts and how the resulting pictures
are appreciated. The findings stem from people who used the camera for a week.
This is complemented with reflections from the researcher, who has been using
the camera for a month.

Urban environments are increasingly filled with digital display systems that
are inflexible, flat, bounded, high-resolution, and unresponsive. In this
paper, we explore the potential of physically instantiated pixels that enable
flexible, reconfigurable, unbounded, low-resolution, and responsive urban
displays. Urban Pixels are nodes in a wireless network of physical pixels for
urban spaces. Each pixel unit includes a microcontroller, RF transceiver (433
MHz), LED module (ten bright, white LEDs), rechargeable Li-Ion battery pack, IR
sensor and renewable energy source such as photo-voltaic cells. Two acrylic
half-spheres (4-inch diameter) protect the components from the elements. No
additional wiring is needed for communication and the units can be mounted
individually to any surface. A small-scale prototype network of fifty Urban
Pixels was displayed on a façade of Eden Court Theater in Inverness,
Scotland from June 1 - June 7, 2008. The public was encouraged to change
display patterns via SMS or to interact with individual units via flashlights.
We observed and informally interviewed theater guests and passers-by
interacting with the façade for several nights. Based on these results,
we outline an exciting problem space for designing displays and lighting
systems in cities.

Programming tools and architectures

This paper describes the ESPranto Software Development Kit, which supports
the development of sensor/actuator based applications, most notably educational
toys and games. It enables non-technical users, such as parents, teachers, game
developers and psychologists, to specify applications by themselves. The SDK
allows them to start off quickly with developing simple applications. Then, as
their programming skills increase with experience, the SDK supports them to
create more complex applications. This is achieved by offering a complete tool
chain with one, consistent programming paradigm. Each link is a separate tool
offering a tailored amount of flexibility and complexity. To ensure that users
can understand the feedback the SDK provides them, it is given in terms of the
tool currently used. Furthermore, by preventing runtime errors, a user can be
sure a program will work correctly if it compiles. We validated the ESPranto
SDK partially by tests, but mainly by monitoring users applying the SDK. In
practice the ESPranto SDK indeed proved to meet its design goals for all of its
intended users.

Intelligibility and control are important user concerns in context-aware
applications. They allow a user to understand why an application is behaving a
certain way, and to change its behavior. Because of their importance to end
users, they must be addressed at an interface level. However, often the sensors
or machine learning systems that users need to understand and control are
created long before a specific application is built, or created separately from
the application interface. Thus, supporting interface designers in building
intelligibility and control into interfaces requires application logic and
underlying infrastructure to be exposed in some structured fashion. As
context-aware infrastructures do not provide generalized support for this, we
extended one such infrastructure with Situations, components that appropriately
exposes application logic, and supports debugging and simple intelligibility
and control interfaces, while making it easier for an application developer to
build context-aware applications and facilitating designer access to
application state and behavior. We developed support for interface designers in
Visual Basic and Flash. We demonstrate the usefulness of this support through
an evaluation of programmers, an evaluation of the usability of the new
infrastructure with interface designers, and the augmentation of three common
context-aware applications.

This paper addresses interaction in multi-surface environments and questions
whether the current application-centric approaches to user interfaces are
adequate in this context, and presents an alternative approach based on
instrumental interaction. The paper presents the VIGO (Views, Instruments,
Governors and Objects) architecture and describes a prototype implementation.
It then illustrates how to apply VIGO to support distributed interaction.
Finally, it demonstrates how a classical Ubicomp interaction technique,
Pick-and-Drop, can be easily implemented using VIGO.

The status of ethnography in systems design

We review the current status of ethnography in systems design. We focus
particularly on new approaches to and understandings of ethnography that have
emerged as the computer has moved out of the workplace. These seek to implement
a different order of ethnographic study to that which has largely been employed
in design to date. In doing so they reconfigure the relationship ethnography
has to systems design, replacing detailed empirical studies of situated action
with studies that provide cultural interpretations of action and critiques of
the design process itself. We hold these new approaches to and understandings
of ethnography in design up to scrutiny, with the purpose of enabling designers
to appreciate the differences between new and existing approaches to
ethnography in systems design and the practical implications this might have
for design.

Keywords: ethnography, ethnomethodology, systems design

Security

A comprehensive study of frequency, interference, and training of multiple
graphical passwords

Graphical password systems have received significant attention as one
potential solution to the need for more usable authentication, but nearly all
prior work makes the unrealistic assumption of studying a single password. This
paper presents the first study of multiple graphical passwords to
systematically examine frequency of access to a graphical password,
interference resulting from interleaving access to multiple graphical
passwords, and patterns of access while training multiple graphical passwords.
We find that all of these factors significantly impact the ease of
authenticating using multiple facial graphical passwords. For example,
participants who accessed four different graphical passwords per week were ten
times more likely to completely fail to authenticate than participants who
accessed a single password once per week. Our results underscore the need for
more realistic evaluations of the use of multiple graphical passwords, have a
number of implications for the adoption of graphical password systems, and
provide a new basis for comparing proposed graphical password systems.

In this work we ask the question: what are the challenges of managing a
physical or file system access-control policy for a large organization? To
answer the question, we conducted a series of interviews with thirteen
administrators who manage access-control policy for either a file system or a
physical space. Based on these interviews we identified three sets of
real-world requirements that are either ignored or inadequately addressed by
technology: 1) policies are made/implemented by multiple people; 2) policy
makers are distinct from policy implementers; and 3) access-control systems
don't always have the capability to implement the desired policy. We present
our interview results and propose several possible solutions to address the
observed issues.

Keywords: access control, policy creation

Awareness, training and trust in interaction with adaptive spam filters

Even though adaptive (trainable) spam filters are a common example of
systems that make (semi-)autonomous decisions on behalf of the user, trust in
these filters has been underexplored. This paper reports a study of usage of
spam filters in the daily workplace and user behaviour in training these
filters (N=43). User observation, interview and survey techniques were applied
to investigate attitudes towards two types of filters: a user-adaptive
(trainable) and a rule-based filter. While many of our participants invested
extensive effort in training their filters, training did not influence filter
trust. Instead, the findings indicate that users' filter awareness and
understanding seriously impacts attitudes and behaviour. Specific examples of
difficulties related to awareness of filter activity and adaptivity are
described showing concerns relevant to all adaptive and (semi-)autonomous
systems that rely on explicit user feedback.

Authentication in public spaces is a risky task. Frauds on cash machines
(ATMs) are not uncommon nowadays. The biggest group of attacks is observation
attacks, which focus on recording the input done by the users. In this work, we
present VibraPass, a system created to be resilient against observation attacks
using tactile feedback provided by the users' own mobile devices. In this way,
secret information is shared between the terminal and the users to add an
over-head of 'lies' to the input which makes it hard for attackers to steal the
real PIN or password. We present an evaluation, which shows that VibraPass has
the potential to replace current authentication systems due to increased
security combined with reasonable input speed and error rates.

Keywords: authentication, lie input, public terminals, security

Techniques for mobile interaction

The Graspables project is an exploration of how measuring the way people
hold and manipulate objects can be used as a user interface. As computational
ability continues to be implemented in more and more objects and devices, new
interaction methods need to be developed. The Graspables System is embodied by
a physical set of sensors combined with pattern recognition software that can
determine how users hold a device. The Graspables System has been implemented
in two prototypes, the Bar of Soap and the Ball of Soap. Applications developed
for these prototypes demonstrate the effectiveness of grasp-recognition as an
interface in multiple scenarios.

The input vocabulary for touch-screen interaction on handhelds is
dramatically limited, especially when the thumb must be used. To enrich that
vocabulary we propose to discriminate, among thumb gestures, those we call
MicroRolls, characterized by zero tangential velocity of the skin relative to
the screen surface. Combining four categories of thumb gestures, Drags, Swipes,
Rubbings and MicroRolls, with other classification dimensions, we show that at
least 16 elemental gestures can be automatically recognized. We also report the
results of two experiments showing that the roll vs. slide distinction
facilitates thumb input in a realistic copy and paste task, relative to
existing interaction techniques.

Gesture recognition is emerging as an engaging interaction technique in
mobile scenarios, and high recognition rates promote user acceptance. Several
factors influence recognition rates including the nature of the gesture set and
the suitability of the gesture recognition algorithm. This work explores how
seamfulness in gesture stroke visualization affects recognition rates. We
present the results of a user evaluation of a gesture recognition system that
shows that raw (seamful) visualization of low-delity gesture stroke data has
recognition rates comparable to no feedback. Providing filtered (seamless)
stroke visualization to the user, while retaining the un-filtered input data
for recognition, resulted in a 34.9% improvement in gesture recognition rate
over raw stroke data. The results provide insights into the broader design
space of seamful design, and identifies areas where seamlessness is
advantageous.

Keywords: gesture recognition, mobile phones, seamful design

Where to locate wearable displays?: reaction time performance of visual
alerts from tip to toe

Advances in electronics have brought the promise of wearable computers to
near reality. Such systems can offer a highly personal and mobile information
and communication infrastructure. Previous research has investigated where
wearable computers can be located on the human body -- critical for successful
development and acceptance. However, for a location to be truly useful, it
needs to not only be accessible for interaction, socially acceptable,
comfortable and sufficiently stable for electronics, but also effective at
conveying information. In this paper, we describe the results from a study that
evaluated reaction time performance to visual stimuli at seven different body
locations. Results indicate that there are numerous and statistically
significant differences in the reaction time performance characteristics of
these locations. We believe our findings can be used to inform the design and
placement of future wearable computing applications and systems.

Social networking sites

Social networking sites (SNS) are only as good as the content their users
share. Therefore, designers of SNS seek to improve the overall user experience
by encouraging members to contribute more content. However, user motivations
for contribution in SNS are not well understood. This is particularly true for
newcomers, who may not recognize the value of contribution. Using server log
data from approximately 140,000 newcomers in Facebook, we predict long-term
sharing based on the experiences the newcomers have in their first two weeks.
We test four mechanisms: social learning, singling out, feedback, and
distribution.
In particular, we find support for social learning: newcomers who see their
friends contributing go on to share more content themselves. For newcomers who
are initially inclined to contribute, receiving feedback and having a wide
audience are also predictors of increased sharing. On the other hand, singling
out appears to affect only those newcomers who are not initially inclined to
share. The paper concludes with design implications for motivating newcomer
sharing in online communities.

Online communities displaying textual postings require measures to combat
information overload. One popular approach is to ask participants whether or
not messages are helpful in order to then guide others to interesting content.
Adopting a well-established framework for assessing data quality, we examine
the nature of "helpfulness."We study consumer reviews at Amazon.com, deriving
22 measures quantifying their textual properties, authors' reputations and
product characteristics. Confirmatory factor analysis reveals five underlying
quality dimensions representing reviewers' reputations in the community, the
topical relevancy of the reviews, the ease of understanding them, their
believability and objectivity. A correlation and regression analysis confirms
that these dimensions are related to the helpfulness scores assigned by
community participants. However, it also uncovers a strong relationship between
the chronological ordering of reviews and helpfulness, which both community
participants and designers should keep in mind when using this method of social
navigation.

We propose that a fundamental property of human psychology, the need to
maintain independent social spheres, imposes constraints on the use of social
network sites (SNS). We particularly focus on the consequences of visibility of
communications across social spheres, and we hypothesize that technological
features of SNS may bring social spheres in conflict, thus leading to increased
levels of online social tension. A survey study among Facebook users was
conducted to test this hypothesis. Results showed that diversity of the
Facebook network predicted online tension. Moreover, the number of kin in a
Facebook network was a crucial component because it predicted online tension
whereas number of work and social contacts did not. Further, evidence was found
to support the idea that tension might impose an upper limit on network size.
We conclude with a discussion of these findings and describe how they support
the thrust of recent modifications to SNS designs.

Keywords: SNS, network diversity, online tension, social spheres

Software developers and programmers

Comparing the use of tangible and graphical programming languages for
informal science education

Much of the work done in the field of tangible interaction has focused on
creating tools for learning; however, in many cases, little evidence has been
provided that tangible interfaces offer educational benefits compared to more
conventional interaction techniques. In this paper, we present a study
comparing the use of a tangible and a graphical interface as part of an
interactive computer programming and robotics exhibit that we designed for the
Boston Museum of Science. In this study, we have collected observations of 260
museum visitors and conducted interviews with 13 family groups. Our results
show that visitors found the tangible and the graphical systems equally easy to
understand. However, with the tangible interface, visitors were significantly
more likely to try the exhibit and significantly more likely to actively
participate in groups. In turn, we show that regardless of the condition,
involving multiple active participants leads to significantly longer
interaction times. Finally, we examine the role of children and adults in each
condition and present evidence that children are more actively involved in the
tangible condition, an effect that seems to be especially strong for girls.

We present design concepts and related mockups that support the user
experience for projects hosted on CodePlex, an open source project hosting
website. Rationale for the design concepts is grounded in the open source
literature and a thirteen-week study with the CodePlex team. We propose that
fostering ways to build trust, providing opportunities for merit, supporting
crossover of work activities, and supporting user experience (UX) best
practices in CodePlex will help dismantle the social and technological barriers
for UX and encourage UX designer participation. We address UX designer
motivation as a challenge for participation and conclude that the mockups
presented are a first step in furthering the user experience in open source
software development.

Some of the most interesting differences between Open Source Software (OSS)
development and commercial co-located software development lie in the
communication and collaboration practices of these two groups of developers.
One interesting practice is that of diagramming. Though well studied and
important in many aspects of co-located software development (including
communication and collaboration among developers), its role in OSS development
has not been thoroughly studied. In this paper, we report our investigation on
how and why Ubuntu contributors use diagrams in their work. Our study shows
that diagrams are not actively used in many scenarios where they commonly would
in co-located software development efforts. We describe differences in the use
and practices of diagramming, their possible reasons, and present design
considerations for potential systems aimed at better supporting diagram use in
OSS development.

Large displays/multi-display environments

With the ever increasing amount of digital information, users desire more
screen real estate to process their daily computing work, and might well
benefit from using a wall-size large high-resolution display instead of a
desktop one. Unfortunately, we know very little about users' behaviors when
using such a display for daily computing. We present a week-long study that
investigates large display use in a personal desktop computing context by
comparing it with single and dual desktop monitor use. Results show users'
unanimous preference for using a large display: it facilitates multi-window and
rich information tasks, enhances users' awareness of peripheral applications,
and offers a more immersive experience. Further, the data reveals distinct
usage patterns in partitioning screen real estate and managing windows on a
large display. Detailed analysis of these results provides insights into
designing interaction techniques and window management systems more suited to a
large display.

One of the core challenges now facing smart rooms is supporting realistic,
everyday activities. While much research has been done to push forward the
frontiers of novel interaction techniques, we argue that technology geared
toward widespread adoption requires a design approach that emphasizes
straightforward configuration and control, as well as flexibility. We examined
the work practices of users of a large, multi-purpose conference room, and
designed DICE, a system to help them use the room's capabilities. We describe
the design process, and report findings about the system's usability and about
people's use of a multi-purpose conference room.

Keywords: smart environments, ubiquitous computing, usability

Arrow tag: a direction-key-based technique for rapidly selecting hyperlinks
while gazing at a screen

Television sets and video game consoles equipped with a web browser have
appeared, and we are now able to browse web pages on television screens.
However, existing navigation techniques are too difficult in this situation. In
this paper, we propose Arrow Tag, a new link selection technique for web
browsers on TV. In this technique, sequences of arrow signs called Arrow Tags
are assigned to the links of the web pages, so users can select the links by
pushing the four direction keys a few times, while keeping her/his gaze fixed
on the television screen. User studies show that Arrow Tag significantly
outperforms the conventional techniques of Focus Move and Number Tag. Moreover,
most participants preferred Arrow Tag over either Focus Move or Number Tag.

Keywords: direction keys, target selection, tv, web browser

What's "this" you say?: the use of local references on distant displays

This study explores how the design of visual display configurations relates
to linguistic expressions. Twenty-five participants performed a series of
object identification and narrative Description tasks on either a large
wall-sized or small desktop display. Results revealed that during the
Description tasks, large display users produced significantly greater rates of
local deictic references than small display users, but in the identification
tasks, the rates were similar for both large and small display users.
Implications for the design of interactive technologies are discussed.

Keywords: discourse, field of view, language, large display

Sustainability 2

It's not easy being green: understanding home computer power management

Although domestic computer use is increasing, most efforts to reduce energy
use through improved power management have focused on computers in the
workplace. We studied 20 households to understand how people use power
management strategies on their home computers. We saw computers in the home,
particularly desktop computers, are left on much more than they are actively
used suggesting opportunities for economic and energy savings. However, for
most of our participants, the economic incentives were too minor to motivate
them to turn off devices when not in use, especially given other frustrations
such as long boot up times. We suggest research directions for home computer
power management that could help users be more green without having to
dramatically change their home computing habits.

The greatest contributor of CO2 emissions in the average American household
is personal transportation. Because transportation is inherently a mobile
activity, mobile devices are well suited to sense and provide feedback about
these activities. In this paper, we explore the use of personal ambient
displays on mobile phones to give users feedback about sensed and self-reported
transportation behaviors. We first present results from a set of formative
studies exploring our respondents' existing transportation routines,
willingness to engage in and maintain green transportation behavior, and
reactions to early mobile phone "green" application design concepts. We then
describe the results of a 3-week field study (N=13) of the UbiGreen
Transportation Display prototype, a mobile phone application that
semi-automatically senses and reveals information about transportation
behavior. Our contributions include a working system for semi-automatically
tracking transit activity, a visual design capable of engaging users in the
goal of increasing green transportation, and the results of our studies, which
have implications for the design of future green applications.

This paper takes up the problem of understanding why we preserve some things
passionately and discard others without thought. We briefly report on the
theoretical literature relating to this question, both in terms of existing
literature in HCI, as well as in terms of related literatures that can advance
the understanding for the HCI community. We use this reading to refine our
frameworks for understanding durability in digital artifice as an issue of
sustainable interaction design in HCI. Next, we report in detail on our ongoing
work in collecting personal inventories of digital artifice in the home
context. We relate our prior and most current personal inventories collections
to the framework that owes to our reading of the theoretical literature.
Finally, we summarize the theoretical implications and findings of our personal
inventories work in terms of implications for the design of digital artifice in
a manner that is more durable.

Tabletop gestures

Current multi-touch interaction techniques typically only use the x-y
coordinates of the human finger's contact with the screen. However, when
fingers contact a touch-sensitive surface, they usually approach at an angle
and cover a relatively large 2D area instead of a precise single point. In this
paper, a Frustrated Total Internal Reflection (FTIR) based multi-touch device
is used to collect the finger imprint data. We designed a series of experiments
to explore human finger input properties and identified several useful
properties such as contact area, contact shape and contact orientation which
can be exploited to improve the performance of multi-touch selecting and
pointing tasks. Based on the experimental results, we discuss some implications
for the design of human finger input interfaces and propose several design
prototypes which incorporate these implications. A set of raw data and several
concrete recommendations which are useful for the research community are also
presented.

We explore the use of multi-finger input to emulate full mouse
functionality, such as the tracking state, three buttons, and chording. We
first present the design space for such techniques, which serves as a guide for
the systematic investigation of possible solutions. We then perform a series of
pilot studies to come up with recommendations for the various aspects of the
design space. These pilot studies allow us to arrive at a recommended
technique, the SDMouse. In a formal study, the SDMouse was shown to
significantly improve performance in comparison to previously developed mouse
emulation techniques.

Many surface computing prototypes have employed gestures created by system
designers. Although such gestures are appropriate for early investigations,
they are not necessarily reflective of user behavior. We present an approach to
designing tabletop gestures that relies on eliciting gestures from
non-technical users by first portraying the effect of a gesture, and then
asking users to perform its cause. In all, 1080 gestures from 20 participants
were logged, analyzed, and paired with think-aloud data for 27 commands
performed with 1 and 2 hands. Our findings indicate that users rarely care
about the number of fingers they employ, that one hand is preferred to two,
that desktop idioms strongly influence users' mental models, and that some
commands elicit little gestural agreement, suggesting the need for on-screen
widgets. We also present a complete user-defined gesture set, quantitative
agreement scores, implications for surface technology, and a taxonomy of
surface gestures. Our results will help designers create better gesture sets
informed by user behavior.

Visualization 1

People's ability to accurately locate target objects in images is severely
affected by the prevalence of the sought objects. This negative effect greatly
impacts critical real world tasks, such as baggage screening and cell slide
pathology, in which target objects are rare. We present three novel image
presentation techniques that are designed to improve visual search. Our
techniques rely on the images being broken into image segments, which are then
recombined or displayed in novel ways. The techniques and their underlying
design reasoning are described in detail, and three experiments are presented
that provide initial evidence that these techniques lead to better search
performance in a simulated cell slide pathology task.

PhotoScope visualizes the spatiotemporal coverage of photos in a photo
collection. It extends the standard photo browsing paradigm in two main ways:
visualizing spatial coverage of photos, and indexing photos by a combination of
spatial coverage, time, and content specifications. This approach enables users
to browse and search space- and time-indexed photos more effectively. We
designed PhotoScope specifically to address challenges in the construction
management industry, where large photo collections are amassed to document
project progress. These ideas may also apply to any photo collection that is
spatially constrained and must be searched using spatial, temporal, and content
criteria. We describe the design choices made when developing PhotoScope and
the results of user evaluation.

Scientists, engineers, and educators commonly need to make graphs that
quickly illustrate quantitative ideas yet are not based on specific data sets.
We call these graphs quantitative concept diagrams (QCDs). Existing charting
and illustration programs make it possible to produce such graphs, but they are
so time-consuming that users tend to sketch the graphs by hand instead. To
reduce the cost of creating QCDs, we developed Graph Sketcher, a quantitative
graphing tool that deeply integrates the data plotting capabilities of charting
programs with the direct manipulation techniques of illustration programs. We
show that our integrated interface substantially reduces the time needed to
create QCDs, and we further show that real Graph Sketcher users both enjoy and
take advantage of the interface improvements to create QCDs in a wide range of
fields.

Urban designers and urban planners often conduct site visits prior to a
design activity to search for patterns or better understand existing
conditions. We introduce SiteLens, an experimental system and set of techniques
for supporting site visits by visualizing relevant virtual data directly in the
context of the physical site, which we call situated visualization. We address
alternative visualization representations and techniques for data collection,
curation, discovery, comparison, manipulation, and provenance. A real use
scenario is presented and two iterations of evaluation with faculty and
students from the Columbia University Graduate School of Architecture, Planning
and Preservation provide directions and insight for further investigation.

Design theory

We report results from interviews with HCI design researchers on their
perceptions of how their research relates to the more traditional scientific
goal of providing explanations. Theories of explanation are prominent in the
physical and natural sciences, psychology, the social sciences, and
engineering. Little work though has so-far addressed the special case of how
results from reflective design of interactive systems can help provide
explanations. We found conceptions of explanation in design research to be
broader and more inclusive than those commonly found in the philosophy of
science. We synthesized concepts from the interviews into a framework which may
help researchers understand how their contributions relate to both classical
and emergent conceptions of explanation.

This paper develops vocabulary to discuss the phenomena related to the new
design paradigm, which considers designing as a situated and constructive
activity of meaning making rather than as problem solving. The paper studies
how design projects proceed from the fuzzy early phases towards the issues of
central relevance to designing. A central concept is framing, and it is
elaborated with examples from two case studies. Several aspects of framing are
explicated, exploratory, anticipatory and social framing, and related concepts
of 'focusing', 'priming', and 'grounding' are explained. The paper concludes
that understanding designing as a situated and constructive making of meaning
has bearings on how designing needs to be supported.

The Value Sensitive Design (VSD) methodology provides a comprehensive
framework for advancing a value-centered research and design agenda. Although
VSD provides helpful ways of thinking about and designing value-centered
computational systems, we argue that the specific mechanics of VSD create
thorny tensions with respect to value sensitivity. In particular, we examine
limitations due to value classifications, inadequate guidance on empirical
tools for design, and the ways in which the design process is ordered. In this
paper, we propose ways of maturing the VSD methodology to overcome these
limitations and present three empirical case studies that illustrate a family
of methods to effectively engage local expressions of values. The findings from
our case studies provide evidence of how we can mature the VSD methodology to
mitigate the pitfalls of classification and engender a commitment to reflect on
and respond to local contexts of design.

New media experiences 1

An increasingly large number of users connect to virtual worlds on a regular
basis to conduct activities ranging from gaming to business meetings. In all
these worlds, users project themselves into the environment via an avatar: a 3D
body which they control and whose appearance is often customizable. However,
considering the prevalence of this form of embodiment, there is a surprising
lack of data about how and why users customize their avatar, as well as how
easy and satisfying the existing avatar creation tools are. In this paper, we
report on a study investigating these issues through a questionnaire
administered to more than a hundred users of three virtual worlds offering
widely different avatar creation and customization systems (Maple Story, World
of Warcraft, and Second Life). We illustrate the often-surprising choices users
make when creating their digital representation and discuss the impact of our
findings for the design of future avatar creation systems.

Virtual worlds (VWs) such as Second Life (SL) contain a rich social culture
where people engage in a multitude of experiences much like real life. With
this comes the need to capture and share memories with others. To understand
what tools people use to accomplish this and what limitations they may face, we
conducted interviews with participants in SL. Our results identify two clusters
of users -- Casuals and Lifers -- who differed in the ways in which they
captured and shared memories. Here we describe the use of photos, landmarks,
friend lists, and conversation logs. We also show how a lack of real life
physical and social constraints in the VW affects user routines, and, in some
cases, how it does not. This suggests design directions for memory tools in the
VW and also real life that break the bounds of current everyday practice.

The novel experience Anywhere allowed participants to explore an urban area,
tying together information not normally available, new points of views and
interaction embedded into physical places. Guided by 'unseen', on-the-street
performers in an ongoing conversation maintained over mobile phones, they
gained access to locative media and staged performances. Our analysis
demonstrates how Anywhere produced engaging and uniquely personalised paths
through a complex landscape of content, negotiated by the performer-participant
pair around various conflicting constraints. We reflect our analysis through
the lens of the key characteristics exhibited by mechanisms that support city
exploration, before focussing on possible extensions to the technological
support of teams of professional and amateur guides.

Keywords: city guide, locative experiences, performance

Classifying and recommending content

Input-agreement: a new mechanism for collecting data using human computation
games

Since its introduction at CHI 2004, the ESP Game has inspired many similar
games that share the goal of gathering data from players. This paper introduces
a new mechanism for collecting labeled data using "games with a purpose." In
this mechanism, players are provided with either the same or a different
object, and asked to describe that object to each other. Based on each other's
descriptions, players must decide whether they have the same object or not. We
explain why this new mechanism is superior for input data with certain
characteristics, introduce an enjoyable new game called "TagATune" that
collects tags for music clips via this mechanism, and present findings on the
data that is collected by this game.

Eliciting user preferences for large datasets and creating rankings based on
these preferences has many practical applications in community-based sites.
This paper gives a new method to elicit user preferences that does not ask
users to tell what they prefer, but rather what a random person would prefer,
and rewards them if their prediction is correct. We provide an implementation
of our method as a two-player game in which each player is shown two images and
asked to click on the image their partner would prefer. The game has proven to
be enjoyable, has attracted tens of thousands of people and has already
collected millions of judgments. We compare several algorithms for combining
these relative judgments between pairs of images into a total ordering of all
images and present a new algorithm to perform collaborative filtering on
pair-wise relative judgments. In addition, we show how merely observing user
preferences on a specially chosen set of images can predict a user's gender
with high probability.

Recommender systems traditionally recommend individual items. We introduce
the idea of collection recommender systems and describe a design space for them
including 3 main aspects that contribute to the overall value of a collection:
the value of the individual items, co-occurrence interaction effects, and order
effects including placement and arrangement of items. We then describe an
empirical study examining how people create mix tapes. The study found
qualitative and quantitative evidence for order effects (e.g., first songs are
rated higher than later songs; some songs go poorly together sequentially). We
propose several ideas for research in this space, hoping to start a much longer
conversation on collection recommender systems.

Using tabletops for education, science, and media

In this paper we compare the affordances of presenting educational material
on a tabletop display with presenting the same material using traditional paper
handouts. Ten pairs of undergraduate students used digital or paper materials
to prepare for exams during four one-hour study sessions over the course of a
term. Students studying with the tabletop display solved problems on their own
before resorting to answer keys and repeated activities more often than
students studying with paper documents. We summarize study activities and
discuss the benefits and drawbacks of each medium.

We present WeSpace -- a collaborative work space that integrates a large
data wall with a multi-user multi-touch table. WeSpace has been developed for a
population of scientists who frequently meet in small groups for data
exploration and visualization. It provides a low overhead walk-up and share
environment for users with their own personal applications and laptops. We
present our year-long effort from initial ethnographic studies, to iterations
of design, development and user testing, to the current experiences of these
scientists carrying out their collaborative research in the WeSpace. We shed
light on the utility, the value of the multi-touch table, the manifestation,
usage patterns and the changes in their workflow that WeSpace has brought
about.

We present CThru, a self-guided video-based educational environment in a
large multi-display setting. We employ a video-centered approach, creating and
combining multimedia contents of different formats with a story-telling
education video. With the support of new display form factors in the
environment, viewing a sequential educational video thread is replaced by the
immersive learning experience of hands-on exploration and manipulation in a
multi-dimensional information space. We demonstrate CThru with an animation
clip in cellular biology, supplementing visible objects in the video with rich
domain-specific multimedia information and interactive 3D models. We describe
CThru's design rationale and implementation. We also discuss a pilot study and
what it revealed with respect to CThru's interface and the usage pattern of the
tabletop and the associated large wall display.

In this paper we describe VPlay, a multi-touch tabletop application that
allows users to mix and manipulate multiple video streams in real-time. Our aim
is to explore how such an interactive surface can support and augment practices
around VJing -- a form of video performance art that is becoming increasingly
popular in nightclubs and other music events. We conclude with observations
from a field deployment, which highlight some initial thoughts and reflections
on our design rationale.

Helping out users with "extreme jobs"

Failure to address extreme environments constraints at the human-computer
interaction level may lead to the commission of critical and potentially fatal
errors. This experimental study addresses gaps in our current theoretical
understanding of the impact of ±Gz accelerations and field dependency
independency on task performance in human-computer interaction. It investigates
the effects of ±Gz accelerations and field dependency independency on
human performance in the completion of perceptual-motor tasks on a personal
digital assistant (PDA). We report the results of a controlled experiment,
conducted in an aerobatic aircraft under multiple ±Gz conditions,
showing that cognitive style significantly impacts latency and accuracy in
target acquisition for perceptual-motor tasks in altered ±Gz
environments and propose design guidelines as countermeasures. Based on the
results, we argue that developing design requirements taking into account
cognitive differences in extreme environments will allow users to execute
perceptual-motor tasks efficiently without unnecessarily increasing cognitive
load and the probability of critical errors.

Ninety million Americans have inadequate health literacy, resulting in a
reduced ability to read and follow directions in the healthcare environment. We
describe an animated, empathic virtual nurse interface for educating and
counseling hospital patients with inadequate health literacy in their hospital
beds at the time of discharge. The development methodology, design rationale,
and two iterations of user testing are described. Results indicate that
hospital patients with low health literacy found the system easy to use,
reported high levels of satisfaction, and most said they preferred receiving
the discharge information from the agent over their doctor or nurse. Patients
also expressed appreciation for the time and attention provided by the virtual
nurse, and felt that it provided an additional authoritative source for their
medical information.

We attached a small LCD display and video camera to a surgical drill. The
LCD shows the tool position with respect to a planned trajectory, overlaid on
video captured by the camera. We performed a user study to determine whether
such a tool-mounted guidance display yields faster and more accurate tool
placement than the conventional guidance display on a separate computer
monitor. Our study showed that the tool-mounted display provides better
positional and angular accuracy than the conventional display but that the
video camera provides no significant improvement in error.

This paper presents a new perspective for the design of indoor navigation
support. In contrast to technology oriented approaches coming from Context
Awareness research, we argue for a wider focus that complements the technical
question of providing precise indoor location with the development of more
effective navigation practices based on technology available today. Starting
from research on indoor navigation conducted with the Paris Fire Brigade, we
present two design concepts aimed at supporting firefighters in creating and
finding their own paths, together with some of the design strategies that
informed the creation of these concepts.

Keywords: firefighting, indoor navigation, ubiquitous computing

Visualization 2

EnsembleMatrix: interactive visualization to support machine learning with
multiple classifiers

Machine learning is an increasingly used computational tool within
human-computer interaction research. While most researchers currently utilize
an iterative approach to refining classifier models and performance, we propose
that ensemble classification techniques may be a viable and even preferable
alternative. In ensemble learning, algorithms combine multiple classifiers to
build one that is superior to its components. In this paper, we present
EnsembleMatrix, an interactive visualization system that presents a graphical
view of confusion matrices to help users understand relative merits of various
classifiers. EnsembleMatrix allows users to directly interact with the
visualizations in order to explore and build combination models. We evaluate
the efficacy of the system and the approach in a user study. Results show that
users are able to quickly combine multiple classifiers operating on multiple
feature sets to produce an ensemble classifier with accuracy that approaches
best-reported performance classifying images in the CalTech-101 dataset.

Previous research has shown that faceted browsing is effective and enjoyable
in searching and browsing large collections of data. In this work, we explore
the efficacy of interactive visualization systems in supporting exploration and
sensemaking within faceted datasets. To do this, we developed an interactive
visualization system called FacetLens, which exposes trends and relationships
within faceted datasets. FacetLens implements linear facets to enable users not
only to identify trends but also to easily compare several trends
simultaneously. Furthermore, it offers pivot operations to allow users to
navigate the faceted dataset using relationships between items. We evaluate the
utility of the system through a description of insights gained while experts
used the system to explore the CHI publication repository as well as a database
of funding grant data, and report a formative user study that identified
usability issues.

We investigate techniques for visualizing time series data and evaluate
their effect in value comparison tasks. We compare line charts with horizon
graphs -- a space-efficient time series visualization technique -- across a
range of chart sizes, measuring the speed and accuracy of subjects' estimates
of value differences between charts. We identify transition points at which
reducing the chart height results in significantly differing drops in
estimation accuracy across the compared chart types, and we find optimal
positions in the speed-accuracy tradeoff curve at which viewers performed
quickly without attendant drops in accuracy. Based on these results, we propose
approaches for increasing data density that optimize graphical perception.

User studies and design

This paper describes a system that empowers practitioners to substantially
improve the user experience with call center automation and agents. Unlike
other approaches we analyze the caller experience in live calls end-to-end,
from dialing to hangup. A web-based solution, the Call Browser provides access
to hundreds or thousands of live end-to-end calls, and empowers usability
practitioners and call-center analysts to systematically and efficiently
evaluate the caller experience and identify usability issues. Case studies from
our consulting practice illustrate how this approach reveals issues that remain
hidden to traditional methods, such as log analyses, lab user studies, focus
groups, and design guidelines.

While the collection of behavioral protocols has been common practice in
human-computer interaction research for many years, the analysis of large
protocol data sets is often extremely tedious and time-consuming, and automated
analysis methods have been slow to develop. This paper proposes an automated
method of protocol analysis to find canonical behaviors -- a small subset of
protocols that is most representative of the full data set, providing a
reasonable "big picture" view of the data with as few protocols as possible.
The automated method takes advantage of recent algorithmic developments in
computational vision, modifying them to allow for distance measures between
behavioral protocols. The paper includes an application of the method to
web-browsing protocols, showing how the canonical behaviors found by the method
match well to sets of behaviors identified by expert human coders.

User-Centered Design is surprisingly difficult. One of the biggest issues,
certainly for those with no HCI or usability experience, is a lack of
appreciation of how users think and work. Their assumption is that users will
approach and solve problems in the same way as the designers and developers of
an interactive solution. Extreme examples of this self-as-user outlook is the
belief that interaction problems are either the direct fault of users or the
failure of users to follow instructions (the 'RTFM' syndrome [9]).
This paper explores a psychological explanation of the self-as-user outlook
through Empathizing-Systemizing theory, including a large-scale study (n = 441)
of men and women working in the Information Technology field. The study found
that men whose role was technological had significantly lower empathizing
scores. The results of the study help to explain the self-as-user outlook and
how it needs to be overcome in the design process.

Cognitive modeling and assessment

Understanding and exploiting the abilities of the human visual system is an
important part of the design of usable user interfaces and information
visualizations. Good design enables quick, easy and veridical perception of key
components of that design. An important facet of human vision is its ability to
seemingly effortlessly perform "perceptual organization; it transforms
individual feature estimates into perception of coherent regions, structures,
and objects. We perceive regions grouped by proximity and feature similarity,
grouping of curves by good continuation, and grouping of regions of coherent
texture. In this paper, we discuss a simple model for a broad range of
perceptual grouping phenomena. It takes as input an arbitrary image, and
returns a structure describing the predicted visual organization of the image.
We demonstrate that this model can capture aspects of traditional design rules,
and predicts visual percepts in classic perceptual grouping displays.

This study explores the characteristics of rationale development in a
complex group decision making task and considers design implications for better
supporting rationale development in group decision making. Twelve three-person,
multi-role teams performed three instances of a collaborative decision making
task with physical maps. We used rhetorical structure theory to analyze the
structure of their decision making discourse. We found that groups begin their
reasoning processing by stating and relating information and finish their
reasoning through a point-counterpoint discussion. We also found that
established groups reduced their need to analyze information during the last
moments of a decision. Implications for the design of group decision support
systems to encourage rationale development are presented.

Keywords: cscw, decision making, rationale, rst

Learning to predict information needs: context-aware display as a cognitive
aid and an assessment tool

We discuss the problem of assessing and aiding user performance in dynamic
tasks that require rapid selection among multiple information sources.
Motivated by research in human sequential learning, we develop a system that
learns by observation to predict the information a user desires in different
contexts. The model decides when the display should be updated, which is akin
to the problem of scene segmentation, and then selects the situationally
relevant information display. The model reduces the cognitive burden of
selecting situation-relevant displays. We evaluate the system in a tank video
game environment and find that the system boosts user performance. The fit of
the model to user data provides a quantitative assessment of user behavior,
which is useful in assessing individual differences and the progression from
novice- to expert-level proficiency. We discuss the relative benefits of
adopting a learning approach to predicting information preferences and possible
avenues to reduce the negative consequences of automation.

Finding info online

In this paper, we describe backchan.nl, a web based backchannel system that
focuses on providing greater audience participation during question and answer
sessions. The system allows audience members to use a web-based service to
propose questions and comments, and to vote on the questions of others. Top
rated submissions are projected into the presentation space where audience
members, moderators, and panelists can see them. We discuss the results of
deploying this system at many different kinds of conferences and relate those
results to the particular design of our system, demonstrating how backchannel
systems can be more than just shared chat rooms. From our experience with this
work, we discuss the broader implications of configurable mediated social
spaces and how subtle design decisions can influence user experience.

Communicating the subtleties of a craft technique, like putting a zipper
into a garment or throwing a clay pot, can be challenging even when working
side by side. Yet How-To content -- including text, images, animations, and
videos -- is available online for a wide variety of crafts. We interviewed
people engaged in various crafts to investigate how online resources
contributed to their craft practice. We found that participants sought creative
inspiration as well as technical clarification online. In this domain, keyword
search can be difficult, so supplemental strategies are used. Participants
sought information iteratively, because they often needed to enact their
knowledge in order to evaluate it. Our description of people learning how
allows us to elaborate existing understandings of information-seeking behavior
by considering how search originates and is evaluated in knowledge domains
involving physical objects and physical processes.

The Web is a dynamic, ever-changing collection of information accessed in a
dynamic way. This paper explores the relationship between Web page content
change (obtained from an hourly crawl of over 40K pages) and people's
revisitation to those pages (collected via a large scale log analysis of 2.3M
users). We identify the relationship, or resonance, between revisitation
behavior and the amount and type of changes on those pages. By coupling our
large scale log analysis with a complementary user study we explore the intent
behind the revisitation behavior we observed. Using the notion of resonance to
identify the likely content of interest, we describe a number of ways
interaction with changing and revisited information can be better supported. We
illustrate how understanding the association between change and revisitation
might improve browser, crawler, and search engine design, and present a
specific example of how knowledge of both can enable relevant content to be
highlighted.

Pointing and cursor techniques

We present DynaSpot, a new technique for acquiring targets based on the area
cursor. DynaSpot couples the cursor's activation area with its speed, behaving
like a point cursor at low speed or when motionless. This technique minimizes
visual distraction and allows pointing anywhere in empty space without
requiring an explicit mode switch, thus enabling users to perform common
interactions such as region selections seamlessly. The results of our
controlled experiments show that the performance of DynaSpot can be modeled by
Fitts' law, and that DynaSpot significantly outperforms the point cursor and
achieves, in most conditions, the same level of performance as one of the most
promising techniques to date, the Bubble cursor.

We present a novel method of dynamic C-D gain adaptation that improves
target acquisition for users with motor impairments. Our method, called the
Angle Mouse, adjusts the mouse C-D gain based on the deviation of angles
sampled during movement. When angular deviation is low, the gain is kept high.
When angular deviation is high, the gain is dropped, making the target bigger
in motor-space. A key feature of the Angle Mouse is that, unlike most pointing
facilitation techniques, it is target-agnostic, requiring no knowledge of
target locations or dimensions. This means that the problem of distractor
targets is avoided because adaptation is based solely on the user's behavior.
In a study of 16 people, 8 of which had motor impairments, we found that the
Angle Mouse improved motor-impaired pointing throughput by 10.3% over the
Windows default mouse and 11.0% over sticky icons. For able-bodied users, there
was no significant difference among the three techniques, as Angle Mouse
throughput was within 1.2% of the default. Thus, the Angle Mouse improved
pointing performance for users with motor impairments while remaining
unobtrusive for able-bodied users.

Ninja cursors aim to speed up target selection on large or multiple
monitors. Several cursors are displayed on the screen with one of them selected
as the active cursor. Eye tracking is used to choose the active cursor. An
experiment with 13 participants showed that multiple cursors speed up the
selection over long distances, but not over short distances. Participants felt
the technique was fastest with 4 cursors per monitor, but still preferred to
have only 1 cursor per monitor for their own use.

We investigate the use of two concurrent input channels to perform a
pointing task. The first channel is the traditional mouse input device whereas
the second one is the gaze position. The rake cursor interaction technique
combines a grid of cursors controlled by the mouse and the selection of the
active cursor by the gaze. A controlled experiment shows that rake cursor
pointing drastically outperforms mouse-only pointing and also significantly
outperforms the state of the art of pointing techniques mixing gaze and mouse
input. A theory explaining the improvement is proposed: the global difficulty
of a task is split between those two channels, and the sub-tasks could partly
be performed concurrently.

Keywords: Fitts' law, multi-channel pointing, rake cursor

The beauty dilemma

The "Beauty Dilemma": beauty is valued but discounted in product choice

The empirical study of aesthetics in Human-Computer Interaction (HCI) is
concerned with -- among other topics -- the relationship between beauty and
usability and the general impact of beauty on product choice and use.
Specifically, the present paper explores the notion of a "beauty dilemma" --
the idea that people discount beauty in a choice situation, although they value
it in general (i.e., they are not choosing what makes them happy). We explored
this idea in three studies with a total of over 600 participants. Study 1
revealed a reluctance to pay for beauty due to its hedonic nature (i.e.,
associated with luxury etc.). Study 2 showed that people prefer a more
beautiful product, but justify their choice by referring to spurious advantages
in usability. Finally, Study 3 revealed that a choice situation which requires
a trade-off between beauty and usability, and which offers no further way to
justify choosing beauty, leads to a sharp increase in the preference of
usability. The underlying reasons for this "beauty dilemma" and further
implications are discussed.

New media experiences 2

Auctions, both traditional and electronic, are a pervasive social
organisation for the valuation and exchange of goods and services. Despite the
long-standing interest in integrating internet contributions into the more
traditional auction such initiatives have remained problematic. We consider the
organization of interaction of sales of fine art and antiques and develop a
prototype 'intelligent' gavel system that is designed to enhance remote
participation and ease the flexible ways in which internet contributions are
legitimately integrated into live auctions. We present the findings of a
quasi-naturalistic experiment involving the use of the system by auctioneers
and its consequences for the general development of technologies to support
internet participation in live co-located events.

Designing technologies that support the explanation of museum exhibits is a
challenging domain. In this paper we develop an innovative approach --
providing a robot guide with resources to engage visitors in an interaction
about an art exhibit. We draw upon ethnographical fieldwork in an art museum,
focusing on how tour guides interrelate talk and visual conduct, specifically
how they ask questions of different kinds to engage and involve visitors in
lengthy explanations of an exhibit. From this analysis we have developed a
robot guide that can coordinate its utterances and body movement to monitor the
responses of visitors to these. Detailed analysis of the interaction between
the robot and visitors in an art museum suggests that such simple devices
derived from the study of human interaction might be useful in engaging
visitors in explanations of complex artifacts.

Based on ten years' experience developing interactive camera/projector
systems for public science and culture exhibits, we define a distinct form of
augmented reality focused on social interaction: social immersive media. Our
work abandons GUI metaphors and builds on the language of cinema, casting users
as actors within simulated narrative models. We articulate philosophical goals,
design principles, and interaction techniques that create strong emotional
responses and social engagement through visceral interaction. We describe
approaches to clearly communicate cultural and scientific ideas through the
medium. And we demonstrate how practitioners can design interactions that
promote specific social behaviors in users.

Personal and online information

While most modern web browsers offer history functionality, few people use
it to revisit previously viewed web pages. In this paper, we present the design
and evaluation of Contextual Web History (CWH), a novel browser history
implementation which improves the visibility of the history feature and helps
people find previously visited web pages. We present the results of a formative
user study to understand what factors helped people in finding past web pages.
From this, we developed CWH to be more visible to users, and supported search,
browsing, thumbnails, and metadata. Combined, these relatively simple features
outperformed Mozilla Firefox 3's built-in browser history function, and greatly
reduced the time and effort required to find and revisit a web page.

Sites like YouTube offer vast sources of data for studies of human computer
interaction. However, they also present a number of methodological challenges.
This paper offers an example study of the initial reception of the iPhone 3G
through YouTube. It begins with a quantitative account of the overall shape of
the most frequently viewed returns for an iPhone 3G" search. A content analysis
of the first hundred videos then explores the returns categorized by genre.
Comments on the most popular video "Will It Blend" are analysed using grounded
theory. It is argued that social science methods are not sufficient for a rich
understanding of such material. The paper concludes with an analysis of "Will
it Blend" that draws on cultural and critical theory. It is argued that a
multi-methodological approach is necessary to exploit such data and also to
address the challenges of next generation Human Computer Interaction (HCI).

This paper describes a longitudinal field experiment in personal note-taking
that examines how people capture and use information in short textual notes.
Study participants used our tool, a simple browser-based textual note-taking
utility, to capture personal information over the course of ten days. We
examined the information they kept in notes using the tool, how this
information was expressed, and aspects of note creation, editing, deletion, and
search. We found that notes were recorded extremely quickly and tersely,
combined information of multiple types, and were rarely revised or deleted. The
results of the study demonstrate the need for a tool such as ours to support
the rapid capture and retrieval of short notes-to-self, and afford insights
into how users' actual note-keeping tendencies could be used to better support
their needs in future PIM tools.

Territoriality, the expression of ownership towards an object, can emerge
when social actors occupy a shared social space. In the case of Wikipedia, the
prevailing cultural norm is one that warns against ownership of one's work.
However, we observe the emergence of territoriality in online space with
respect to a subset of articles that have been tagged with the Maintained
template through a qualitative study of 15 editors who have self-designated as
Maintainers. Our participants communicated ownership, demarcated boundaries and
asserted their control over artifacts for the sake of quality by appropriating
existing features of Wikipedia. We then suggest design strategies to support
these behaviors in the proper context within collaborative authoring systems
more generally.

Studying Wikipedia

How is work created, assigned, and completed on large-scale, crowd-powered
systems like Wikipedia? And what design principles might enable these federated
online systems to be more effective? This paper reports on a qualitative study
of work and task practices on Wikipedia. Despite the availability of tag-based
community-wide task assignment mechanisms, informants reported that
self-directed goals, within-topic expertise, and fortuitous discovery are more
frequently used than community-tagged tasks. We examine how Wikipedia editors
organize their actions and the actions of other participants, and what
implications this has for understanding, and building tools for, crowd-powered
systems, or any web site where the main
force of production comes from a crowd of online participants. From these
observations and insights, we developed WikiTasks, a tool that integrates with
Wikipedia and supports both grassroots creation of site-wide tasks and
self-selection of personal tasks, accepted from this larger pool of community
tasks.

Keywords: Wikipedia, crowdsourcing, social software, task management

Coordination in collective intelligence: the role of team structure and task
interdependence

The success of Wikipedia has demonstrated the power of peer production in
knowledge building. However, unlike many other examples of collective
intelligence, tasks in Wikipedia can be deeply interdependent and may incur
high coordination costs among editors. Increasing the number of editors
increases the resources available to the system, but it also raises the costs
of coordination. This suggests that the dependencies of tasks in Wikipedia may
determine whether they benefit from increasing the number of editors involved.
Specifically, we hypothesize that adding editors may benefit low-coordination
tasks but have negative consequences for tasks requiring a high degree of
coordination. Furthermore, concentrating the work to reduce coordination
dependencies should enable more efficient work by many editors. Analyses of
both article ratings and article review comments provide support for both
hypotheses. These results suggest ways to better harness the efforts of many
editors in social collaborative systems involving high coordination tasks.

An experiment was conducted to study how credibility judgments about
Wikipedia are affected by providing users with an interactive visualization
(WikiDashboard) of article and author editing history. Overall, users who
self-reported higher use of Internet information and higher rates of Wikipedia
usage tended to produce lower credibility judgments about Wikipedia articles
and authors. However, use of WikiDashboard significantly increased article and
author credibility judgments, with effect sizes larger than any other measured
effects of background media usage and attitudes on Wikiepedia credibility. The
results suggest that increased exposure to the editing/authoring histories of
Wikipedia increases credibility judgments.

Wikipedia is an online encyclopedia which has undergone tremendous growth.
However, this same growth has made it difficult to characterize its content and
coverage. In this paper we develop measures to map Wikipedia using its socially
annotated, hierarchical category structure. We introduce a mapping technique
that takes advantage of socially-annotated hierarchical categories while
dealing with the inconsistencies and noise inherent in the distributed way that
they are generated. The technique is demonstrated through two applications:
mapping the distribution of topics in Wikipedia and how they have changed over
time; and mapping the degree of conflict found in each topic area. We also
discuss the utility of the approach for other applications and datasets
involving collaboratively annotated category hierarchies.

Multimodal mobile interaction

With an ever increasing number of mobile services, meaningful audio
notifications could effectively inform users of the incoming services while
minimising undesired and intrusive interruptions. Therefore, careful design of
mobile service notification is needed. In this paper we evaluate two types of
audio (auditory icons and earcons) as mobile service notifications, by
comparing them on 4 measures: intuitiveness, learnability, memorability and
user preference. A 4-stage longitudinal evaluation involving two lab
experiments, a field study and a web-based experiment indicated that auditory
icons performed significantly better in all measures. Implications for mobile
audio notification design are presented.

Zooming user interfaces are increasingly popular on mobile devices with
touch screens. Swiping and pinching finger gestures anywhere on the screen
manipulate the displayed portion of a page, and taps open objects within the
page. This makes navigation easy but limits other manipulations of objects that
would be supported naturally by the same gestures, notably cut and paste,
multiple selection, and drag and drop. A popular device that suffers from this
limitation is Apple's iPhone. In this paper, we present Bezel Swipe, an
interaction technique that supports multiple selection, cut, copy, paste and
other operations without interfering with zooming, panning, tapping and other
pre-defined gestures. Participants of our user study found Bezel Swipe to be a
viable alternative to direct touch selection.

Shake2Talk is a mobile messaging system that allows users to send sounds and
tactile sensations to one another via their mobile phones. Messages are created
through gestures and then sent to the receiver's phone where they play upon
arrival. This paper reports a study of the Shake2Talk system in use by six
couples, and begins to uncover the types of messaging practices that occur, and
the values and meanings that users ascribe to these messages.

Current solutions for managing music in mobile contexts are inconvenient as
they require considerable effort and visual attention. We describe a novel
system for exploring music and generating playlists in mobile contexts, and
present findings from our formative usability evaluations. The system provides
audio-tactile feedback and is controlled by manipulating a device's
orientation. The system plays songs associated with the current orientation. A
spatial gesture or other command is then used to lock the orientation into a
playlist. We evaluated two iterations of a prototype of the system and found
that users were successful in exploring music and generating playlists with the
system. We found that certain orientations are more common than others. Also,
manipulating the prototype felt more natural while walking than sitting.
Personalization of the music mapping was requested by users and seen as
beneficial for usability.

In this paper, we present a design and an evaluation of a hand-held
trackball based touch-haptic interface, named "TouchBall." Using a trackball
mechanism, the device provides flexibility in terms of directional degrees of
freedom. It also has an advantage of a direct transfer of force feedback
through frictional touch (with high sensitivity), thus requiring only
relatively small amount of inertia. This leads to a compact hand-held design
appropriate for mobile and 3D interactive applications. The device is evaluated
for the detection thresholds for directions of the force feedback and the
perceived amount of directional force. The refined directionality information
should combine with other modalities with less sensory conflict, enriching the
user experience for a given application.

New gaming experiences

Exertion games are an emerging form of interactive games that require
players to invest significant physical effort as part of the gameplay, rather
than just pressing buttons. These exertion games have potential health benefits
by promoting exercise. It is also believed that they can facilitate social play
between players and that social play can improve participation in exertion
games. However, there is currently a lack of understanding of how to design
games to support these effects. In this paper, we present a qualitative case
study that illustrates how networked environments support social play in
exertion games and how this can help to gain an understanding of existing games
and support the design of future games. This work offers a preliminary
analytical and descriptive account of the relationship between exertion and
social play in such a game and highlights the influence of design with the aim
of utilizing the attributed benefits of exertion and social play.

Pervasive games are staged in reality and their main attractiveness is
generated by using reality as a resource in the game. Yet, most pervasive games
that use mobile and location-based technology use reality only in a weak sense,
as the location for a computerized game.
In this article we analyze two game practices, Nordic style live action
role-playing (larp) and alternate reality games (ARG), that instead use reality
as their main game resource. We analyze how they go about creating a believable
game world and encourage the players to actively take part in this world. We
present two example games that do the same with the support of technology,
effectively realizing an immersive game world through a combination of physical
play and technology-supported play.

In this paper, we present results from a qualitative study of collocated
group console gaming. We focus on motivations for, perceptions of, and
practices surrounding the shared use of console games by a variety of
established groups of gamers. These groups include both intragenerational
groups of youth, adults, and elders as well as intergenerational families. Our
analysis highlights the numerous ways that console games serve as a
computational meeting place for a diverse population of gamers.

Software development

Debugging and diagnostic tools are some of the most important software
development tools, but most expect developers choose the right code to inspect.
Unfortunately, this rarely occurs. A new tool called the Whyline is described
which avoids such speculation by allowing developers to select questions about
a program's output. The tool then helps developers work backwards from output
to its causes. The prototype, which supports Java programs, was evaluated in an
experiment in which participants investigated two real bug reports from an open
source project using either the Whyline or a breakpoint debugger. Whyline users
were successful about three times as often and about twice as fast compared to
the control group, and were extremely positive about the tool's ability to
simplify diagnostic tasks in software development work.

Keywords: debugging, instrumentation, slicing, whyline

Fisheyes in the field: using method triangulation to study the adoption and
use of a source code visualization

Information visualizations have been shown useful in numerous laboratory
studies, but their adoption and use in real-life tasks are curiously
under-researched. We present a field study of ten programmers who work with an
editor extended with a fisheye view of source code. The study triangulates
multiple methods (experience sampling, logging, thinking aloud, and interviews)
to describe how the visualization is adopted and used. At the concrete level,
our results suggest that the visualization was used as frequently as other
tools in the programming environment. We also propose extensions to the
interface and discuss features that were not used in practice. At the
methodological level, the study identifies contributions distinct to individual
methods and to their combination, and discusses the relative benefits of
laboratory studies and field studies for the evaluation of information
visualizations.

This paper investigates the role of online resources in problem solving. We
look specifically at how programmers -- an exemplar form of knowledge workers
-- opportunistically interleave Web foraging, learning, and writing code. We
describe two studies of how programmers use online resources. The first,
conducted in the lab, observed participants' Web use while building an online
chat room. We found that programmers leverage online resources with a range of
intentions: They engage in just-in-time learning of new skills and approaches,
clarify and extend their existing knowledge, and remind themselves of details
deemed not worth remembering. The results also suggest that queries for
different purposes have different styles and durations. Do programmers' queries
"in the wild" have the same range of intentions, or is this result an artifact
of the particular lab setting? We analyzed a month of queries to an online
programming portal, examining the lexical structure, refinements made, and
result pages visited. Here we also saw traits that suggest the Web is being
used for learning and reminding. These results contribute to a theory of online
resource usage in programming, and suggest opportunities for tools to
facilitate online knowledge work.

Keywords: copy-and-paste, opportunistic programming, prototyping

Usability methods

Post-task ratings of difficulty in a usability test have the potential to
provide diagnostic information and be an additional measure of user
satisfaction. But the ratings need to be reliable as well as easy to use for
both respondents and researchers. Three one-question rating types were compared
in a study with 26 participants who attempted the same five tasks with two
software applications. The types were a Likert scale, a Usability Magnitude
Estimation (UME) judgment, and a Subjective Mental Effort Question (SMEQ). All
three types could distinguish between the applications with 26 participants,
but the Likert and SMEQ types were more sensitive with small sample sizes. Both
the Likert and SMEQ types were easy to learn and quick to execute. The online
version of the SMEQ question was highly correlated with other measures and had
equal sensitivity to the Likert question type.

Correlations between prototypical usability metrics from 90 distinct
usability tests were strong when measured at the task-level (r between .44 and
.60). Using test-level satisfaction ratings instead of task-level ratings
attenuated the correlations (r between .16 and .24). The method of aggregating
data from a usability test had a significant effect on the magnitude of the
resulting correlations. The results of principal components and factor analyses
on the prototypical usability metrics provided evidence for an underlying
construct of general usability with objective and subjective factors.

Remote asynchronous usability testing is characterized by both a spatial and
temporal separation of users and evaluators. This has the potential both to
reduce practical problems with securing user attendance and to allow direct
involvement of users in usability testing. In this paper, we report from an
empirical study where we systematically compared three methods for remote
asynchronous usability testing: user-reported critical incidents, forum-based
online reporting and discussion, and diary-based longitudinal user reporting.
In addition, conventional laboratory-based think-aloud testing was included as
a benchmark for the remote methods. The results show that each remote
asynchronous method supports identification of a considerable number of
usability problems. Although this is only about half of the problems identified
with the conventional method, it requires significantly less time. This makes
remote asynchronous methods an appealing possibility for usability testing in
many software projects.

Studying cell phone use

We investigate how people adapt their strategy for interleaving multiple
concurrent tasks to varying objectives. A study was conducted in which
participants drove a simulated vehicle and occasionally dialed a telephone
number on a mobile phone. Experimental instructions and feedback encouraged
participants to focus on either driving or dialing. Results show that
participants adapted their task interleaving strategies to meet the required
task objective, but in a manner that was nonetheless intricately shaped by
internal psychological constraints. In particular, participants tended to steer
in between dialing chunks of digits even when extreme vehicle drift implied
that more reactive strategies would have generated better lane keeping. To
better understand why drivers interleaved tasks at chunk boundaries, a modeling
analysis was conducted to derive performance predictions for a range of dialing
strategies. The analysis supported the idea that interleaving at chunk
boundaries efficiently traded the time given up to dialing with the maintenance
of a central lane position. We discuss the implications of this work in terms
of contributions to understanding how cognitive constraints shape strategy
adaptations in dynamic multitask environments.

We conducted a diary and interview study to investigate where and why people
use cell phones to access the Internet. In more that 50% of the cases, our
participants chose a phone even though they had access to a computer, and the
most frequent location for cell phone Internet access was the home.

Though legislation is increasingly discouraging drivers from holding on to
their mobile phones while talking, hands-free devices do not improve driver
safety. We offer two design alternatives to improve driver safety in the
contexts of voice-based user interfaces and mobile phone conversations in cars'
side tones (auditory feedback used in landline phones) and location of
speakers. In a 2 (side tone: present vs. not) x 2 (location of speakers:
headphones vs. dashboard) between-participants experiment (N=48), we
investigated the impact of these features upon driver experience and
performance on a simulated mobile phone conversation while driving.
Participants became more verbally engaged in the conversation when side tones
were present, but also experienced more cognitive load. Participants drove more
safely when voices were projected from the dashboard rather than from
headphones. Implications for driver user interface design are discussed.

Mobile phones are becoming increasingly personalized in terms of the data
they store and the types of services they provide. At the same time, field
studies have reported that there are a variety of situations in which it is
natural for people to share their phones with others. However, most mobile
phones support a binary security model that offers all-or-nothing access to the
phone. We interviewed 12 smartphone users to explore how security and data
privacy concerns affected their willingness to share their mobile phones. The
diversity of guest user categorizations and associated security constraints
expressed by the participants suggests the need for a security model richer
than today's binary model.

This paper reports on a direct test of social responses to communication
technologies theory (SRCT) with mobile messaging. SRCT predicts that people
will mindlessly respond to computers in social ways that mirror their responses
to humans. A field experiment (N=71) using participants' own mobile phones
compared three influence strategies (direct request, flattery, and social
norms) in the context of asking intimate questions of participants. These
messages came from either an ostensibly human or computer sender. Flattery
significantly increased self-disclosure when ostensibly sent by a human, but
not when from a computer. The interaction effect for sender and influence
strategy is inconsistent with SRCT's predictions. Implications for theories of
source orientation, research methods, and future research are discussed.

Desktop techniques

We introduce ephemeral adaptation, a new adaptive GUI technique that
improves performance by reducing visual search time while maintaining spatial
consistency. Ephemeral adaptive interfaces employ gradual onset to draw the
user's attention to predicted items: adaptively predicted items appear abruptly
when the menu is opened, but non-predicted items fade in gradually. To
demonstrate the benefit of ephemeral adaptation we conducted two experiments
with a total of 48 users to show: (1) that ephemeral adaptive menus are faster
than static menus when accuracy is high, and are not significantly slower when
it is low and (2) that ephemeral adaptive menus are also faster than adaptive
highlighting. While we focused on user-adaptive GUIs, ephemeral adaptation
should be applicable to a broad range of visually complex tasks.

In this paper, we show that people frequently return to previously-visited
regions within their documents, and that scrollbars can be enhanced to ease
this task. We analysed 120 days of activity logs from Microsoft Word and Adobe
Reader. Our analysis shows that region revisitation is a common activity that
can be supported with relatively short recency lists. This establishes an
empirical foundation for the design of an enhanced scrollbar containing
scrollbar marks that helps people return to previously visited document
regions. Two controlled experiments show that scrollbar marks decrease
revisitation time, and that a large number of marks can be used effectively. We
then design an enhanced Footprints scrollbar that supports revisitation with
several features, including scrollbar marks and mark thumbnails. Two further
experiments show that the Footprints scrollbar was frequently used and strongly
preferred over traditional scrollbars.

Copy and move operations have long been supported by interactive desktops
through various means. But the growing number of on-screen objects makes these
means harder to use. In this note, we present new tools and techniques to
enhance the existing ones: a selection, copy and drag history manager; two
techniques to expose the user's desk and leaf through stacks of overlapping
windows; and a technique that integrates the previous two with conventional
drag-and-drop.

Keywords: copy-and-paste, cut-and-paste, drag-and-drop

WikiFolders: augmenting the display of folders to better convey the meaning
of files

Hierarchical file systems and file browsers offer powerful capabilities for
managing and organizing folders and files. Yet they lack robust tools for
annotating and documenting these files-individually or collectively-with
descriptive text. In contrast, Web pages and wikis make it easy to create rich
and meaningful narratives around digital artifacts, allowing files to be
embedded within explanatory text and images. Unfortunately, considerable effort
is required to manage files stored on Web servers and to ensure that the
published content remains up-to-date. In this note, we describe WikiFolders, a
hybrid system for annotating file folders that draws upon the strengths of both
the hierarchical file system and wikis.

Designing for senior citizens

Previous research has shown that older adults performed worse in web search
tasks, and attributed poorer performance to a decline in their cognitive
abilities. We conducted a study involving younger and older adults to compare
their web search behavior and performance in ill-defined and well-defined
information tasks using a health information website. In ill-defined tasks,
only a general description about information needs was given, while in
well-defined tasks, information needs as well as the specific target
information were given. We found that older adults performed worse than younger
adults in well-defined tasks, but the reverse was true in ill-defined tasks.
Older adults compensated for their lower cognitive abilities by adopting a
top-down knowledge-driven strategy to achieve the same level of performance in
the ill-defined tasks. Indeed, path models showed that cognitive abilities,
health literacy, and knowledge influenced search strategies adopted by older
and younger adults. Design implications are also discussed.

This paper offers an exploration of the attitudes of older adults to keeping
in touch with people who are important to them. We present findings from three
focus groups with people from 55 to 81 years of age. Themes emerging from the
findings suggest that older adults view the act of keeping in touch as being
worthy of time and dedication, but also as being something that needs to be
carefully managed within the context of daily life. Communication is seen as a
means through which skill should be demonstrated and personality expressed, and
is understood in a very different context to the lightweight interaction that
is increasingly afforded by new technologies. The themes that emerged are used
to elicit a number of design implications and to promote some illustrative
design concepts for new communication devices.

The domestic environment is more than a place where to live. It is a
territory of meaning, a place where pleasure, affect and aesthetics are deeply
interwoven with the functional and utilitarian dimensions. With the aging
process, the home is progressively invested with new meanings and functions,
and becomes the emotional center of older people's life.
This paper presents a user study based on cultural probes on how domestic
spaces are managed and perceived by older adults, uncovering some of the
complex interrelations among the daily activities, objects and meanings
revolving around the home. The findings provide suggestions on how the
dimensions of remembrance, perception of safety and environmental stability may
affect the design of domestic technology for elderly people.

Keywords: aging, cultural probes, design of domestic technology

Photos and life logging

Baby steps: evaluation of a system to support record-keeping for parents of
young children

Parents of young children often want to keep a variety of records on their
children's early years, for the purposes of preservation of memories or at the
request of their pediatrician. However, time constraints, motivation, and
forgetfulness may hinder their ability to keep consistent records. We developed
a system, Baby Steps, which is designed to improve the record-keeping process.
In this paper, we present the results of a 3-month deployment study of this
technology with 8 families and their pediatricians. The study showed that when
compared to a control condition, experimental design features of Baby Steps
encouraged parents to more frequently collect and review records, provided
higher confidence in reporting, and improved parent-pediatrician communication.

Lifelogging' technology makes it possible to amass digital data about every
aspect of our everyday lives. Instead of focusing on such technical
possibilities, here we investigate the way people compose long-term mnemonic
representations of their lives. We asked 10 families to create a time capsule,
a collection of objects used to trigger remembering in the distant future. Our
results show that contrary to the lifelogging view, people are less interested
in exhaustively digitally recording their past than in reconstructing it from
carefully selected cues that are often physical objects. Time capsules were
highly expressive and personal, many objects were made explicitly for
inclusion, however with little object annotation. We use these findings to
propose principles for designing technology that supports the active
reconstruction of our future past.

In this paper we discuss some of our recent research work designing tabletop
interfaces for co-located photo sharing. We draw particular attention to a
specific feature of an interface design, which we have observed over an
extensive number of uses, as facilitating an under-reported but none-the-less
intriguing aspect of the photo-sharing experience -- namely the process of
'getting sidetracked'. Through a series of vignettes of interaction during
photo-sharing sessions we demonstrate how users of our tabletop photoware
system used peripheral presentation of topically incoherent photos to artfully
initiate new photo-talk sequences in on-going discourse. From this we draw
implications for the design of tabletop photo applications, and for the
experiential analysis of such devices.

In this paper we show that financial information can be used to sense many
aspects of human activity. This simple technique gives people information about
their daily lives, is easily accessible to many at no extra cost, requires
little setup, and does not require the manufacture of any external devices. We
will focus on how financial data can be used to show users where they spend
their time, when they accomplish certain habits, and what the impact of their
activities is on the environment. We validate our idea by implementing three
demonstration applications intended for personal use. Finally, this paper
discusses limitations of sensing using financial data and possible solutions.

Keywords: context-aware computing, ubiquitous computing

Mobile applications for the developing world

A comparison of mobile money-transfer UIs for non-literate and semi-literate
users

Due to the increasing penetration of mobile phones even into poor
communities, mobile payment schemes could bring formal financial services to
the "unbanked". However, because poverty for the most part also correlates with
low levels of formal education, there are questions as to whether electronic
access to complex financial services is enough to bridge the gap, and if so,
what sort of UI is best.
In this paper, we present two studies that provide preliminary answers to
these questions. We first investigated the usability of existing mobile payment
services, through an ethnographic study involving 90 subjects in India, Kenya,
the Philippines and South Africa. This was followed by a usability study with
another 58 subjects in India, in which we compared non-literate and
semi-literate subjects on three systems: text-based, spoken dialog (without
text), and rich multimedia (also without text). Results confirm that non-text
designs are strongly preferred over text-based designs and that while
task-completion rates are better for the rich multimedia UI, speed is faster
and less assistance is required on the spoken-dialog system.

Keywords: illiteracy, mobile banking, mobile interfaces

Comparing semiliterate and illiterate users' ability to transition from
audio+text to text-only interaction

Multimodal interfaces with little or no text have been shown to be useful
for users with low literacy. However, this research has not differentiated
between the needs of the fully illiterate and semiliterate -- those who have
basic literacy but cannot read and write fluently. Text offers a fast and
unambiguous mode of interaction for literate users and the exposure to text may
allow for incidental improvement of reading skills. We conducted two studies
that explore how semiliterate users with very little education might benefit
from a combination of text and audio as compared to illiterate and literate
users. Results show that semiliterate users reduced their use of audio support
even during the first hour of use and over several hours this reduction was
accompanied by a gain in visual word recognition; illiterate users showed no
similar improvement. Semiliterate users should thus be treated differently from
illiterate users in interface design.

Mobile imaging and digital storytelling currently support a growing practice
of multimedia communication in the West. In this paper we describe a project
which explores their benefit in the East, to support non-textual information
sharing in an Indian village. Local audiovisual story creation and sharing
activities were carried out in a one month trial, using 10 customized
cameraphones and a digital library of stories represented on a village display.
The findings show that the system was usable by a cross-section of the
community and valued for its ability to express a mixture of development and
community information in an accessible form. Lessons for the role of HCI in
this context are also discussed.

Social search and sensemaking

Making sense of the information found during an investigational Web search
task can be daunting. With the recent emergence of tools to support
collaborative Web search, the associated sensemaking task has become even more
complex, requiring sense to be made not only of the products of a search (i.e.,
results found) but of the process, as well (i.e., group division of labor and
decision-making).
We present the findings of a formative study illustrating the sensemaking
challenges posed by collaborative search tools. Based on these findings, we
created CoSense, a system that supports sensemaking for collaborative Web
search tasks by providing several rich, interactive views of a group's search
activities. We describe an evaluation of CoSense, reflecting on how its
features supported different aspects of sensemaking, and how future
collaborative search systems can benefit from these findings.

Collaborative web browsing tasks occur frequently, such as one user showing
another how to use a web site, several users working together on a search task,
or even one user sending an interesting link to another user. Unfortunately,
tools for browsing the web are commonly designed for a single user. PlayByPlay
is a general purpose web collaboration tool that uses the communication model
of instant messaging to support a variety of collaborative browsing tasks.
PlayByPlay also supports collaborative browsing between mobile and desktop
users, which we believe is useful for on-the-go scenarios. We conducted user
studies of the desktop and mobile versions of PlayByPlay and found the system
to be usable and effective.

A common practice in work groups is to share links to interesting web pages.
Moreover, passages in these web pages are often cut-and-pasted, and used in
various other contexts. In this paper we report how we explore the idea of
paragraph fingerprinting to achieve the goal of annotate once, appear anywhere
in a social annotation system called SparTag.us. This work was motivated by the
prominence of redundant contents with different URLs on the Web and shared
documents that are read and re-read within enterprises. Our technique attaches
users' annotations to the contents of paragraphs, enabling annotations to move
along with the paragraphs within dynamic live pages and travel across page
boundary to other pages as long as the paragraph contents remain intact. We
also describe how we use paragraph fingerprinting to facilitate the social
sharing of information nuggets among our users.

In prior work we reported on the design of a social annotation system,
SparTag.us, for use in sensemaking activities such as work-group reading and
report writing. Previous studies of note-taking systems have demonstrated
behavioral differences in social annotation practices, but are not clear in the
actual performance gains provided by social features. This paper presents a
laboratory study aimed at evaluating the learning effect of social features in
SparTag.us. We found significant learning gains, and consider implications for
design and for understanding the underlying mechanisms in play when people use
social annotation systems.

Keywords: social annotation systems, social sensemaking, user studies

Understanding UI 2

Self-interruption on the computer: a typology of discretionary task
interleaving

The typical information worker is interrupted every 12 minutes, and half of
the time they are interrupting themselves. However, most of the research on
interruption in the area of human-computer interaction has focused on
understanding and managing interruptions from external sources. Internal
interruptions -- user-initiated switches away from a task prior to its
completion -- are not well understood. In this paper we describe a qualitative
study of self-interruption on the computer. Using a grounded theory approach,
we identify seven categories of self-interruptions in computer-related
activities. These categories are derived from direct observations of users, and
describe the motivation, potential consequences, and benefits associated with
each type of self-interruption observed. Our research extends the understanding
of the self-interruption phenomenon, and informs the design of systems to
support discretionary task interleaving on the computer.

An intriguing anomaly of the usual way of designing Fitts' law experiments
in experimental psychology and HCI is exposed: experiments are traditionally
designed so as to carefully balance two ancillary factors, target distance D
and target width W, but not task difficulty, the factor unanimously thought to
be crucial. Troubling factor confounds and hence quantitative estimation errors
result from this inconsistency. The problem, it is suggested, may be fixed if
the equivocalness of the fractional expression D/W that appears on the
right-hand side of Fitts' law equations is acknowledged. This
two-degree-of-freedom expression can be taken to specify either D and W or the
form F and the scale S of the movement task. The paper ends up with practical
recommendations for the design of consistent Fitts' law experiments. In most
cases eliminating one factor will allow a safer estimation of Fitts' law
parameters, while simplifying the experimental work.

Multitasking in user behavior can be represented along a continuum in terms
of the time spent on one task before switching to another. In this paper, we
present a theory of behavior along the multitasking continuum, from concurrent
tasks with rapid switching to sequential tasks with longer time between
switching. Our theory unifies several theoretical effects -- the ACT-R
cognitive architecture, the threaded cognition theory of concurrent
multitasking, and the memory-for-goals theory of interruption and resumption --
to better understand and predict multitasking behavior. We outline the theory
and discuss how it accounts for numerous phenomena in the recent empirical
literature.

Supporting blind users

Audio CAPTCHAs were introduced as an accessible alternative for those unable
to use the more common visual CAPTCHAs, but anecdotal accounts have suggested
that they may be more difficult to solve. This paper demonstrates in a large
study of more than 150 participants that existing audio CAPTCHAs are clearly
more difficult and time-consuming to complete as compared to visual CAPTCHAs
for both blind and sighted users. In order to address this concern, we
developed and evaluated a new interface for solving CAPTCHAs optimized for
non-visual use that can be added in-place to existing audio CAPTCHAs. In a
subsequent study, the optimized interface increased the success rate of blind
participants by 59% on audio CAPTCHAs, illustrating a broadly applicable
principle of accessible design: the most usable audio interfaces are often not
direct translations of existing visual interfaces.

Advanced web scenarios

Although existing work has explored both information extraction and
community content creation, most research has focused on them in isolation. In
contrast, we see the greatest leverage in the synergistic pairing of these
methods as two interlocking feedback cycles. This paper explores the potential
synergy promised if these cycles can be made to accelerate each other by
exploiting the same edits to advance both community content creation and
learning-based information extraction. We examine our proposed synergy in the
context of Wikipedia infoboxes and the Kylin information extraction system.
After developing and refining a set of interfaces to present the verification
of Kylin extractions as a non primary task in the context of Wikipedia
articles, we develop an innovative use of Web search advertising services to
study people engaged in some other primary task. We demonstrate our proposed
synergy by analyzing our deployment from two complementary perspectives: (1) we
show we accelerate community content creation by using Kylin's information
extraction to significantly increase the likelihood that a person visiting a
Wikipedia article as a part of some other primary task will spontaneously
choose to help improve the article's infobox, and (2) we show we accelerate
information extraction by using contributions collected from people interacting
with our designs to significantly improve Kylin's extraction performance.

We present reform, a step toward write-once apply-anywhere user interface
enhancements. The reform system envisions roles for both programmers and end
users in enhancing existing websites to support new goals. First, a programmer
authors a traditional mashup or browser extension, but they do not write a web
scraper. Instead they use reform, which allows novice end users to attach the
enhancement to their favorite sites with a scraping by-example interface.
reform makes enhancements easier to program while also carrying the benefit
that end users can apply the enhancements to any number of new websites. We
present reform's architecture, user interface, interactive by-example
extraction algorithm for novices, and evaluation, along with five example
reform enabled enhancements.

A key challenge for mixed-initiative systems is to create a shared
understanding of the task between human and agent. To address this challenge,
we created a mixed-initiative interface called Mixer to aid administrators with
automating tedious information-retrieval tasks. Users initiate communication
with the agent by constructing a form, creating a structure to hold the
information they require and to show context in order to interpret this
information. They then populate the form with the desired results,
demonstrating to the agent the steps required to retrieve the information. This
method of form creation explicitly defines the shared understanding between
human and agent. An evaluation of the interface shows that administrators can
effectively create forms to communicate with the agent, that they are likely to
accept this technology in their work environment, and that the agent's help can
significantly reduce the time they spend on repeated information-retrieval
tasks.

Enhancing reality

Visual markers are graphic symbols designed to be easily recognised by
machines. They are traditionally used to track goods, but there is increasing
interest in their application to mobile HCI. By scanning a visual marker
through a camera phone users can retrieve localised information and access
mobile services.
One missed opportunity in current visual marker systems is that the markers
themselves cannot be visually designed, they are not expressive to humans, and
thus fail to convey information before being scanned. This paper provides an
overview of d-touch, an open source system that allows users to create their
own markers, controlling their aesthetic qualities. The system runs in
real-time on mobile phones and desktop computers. To increase computational
efficiency d-touch imposes constraints on the design of the markers in terms of
the relationship of dark and light regions in the symbols. We report a user
study in which pairs of novice users generated between 3 and 27 valid and
expressive markers within one hour of being introduced to the system,
demonstrating its flexibility and ease of use.

We present findings from field trials of MapLens, a mobile augmented reality
(AR) map using a magic lens over a paper map. Twenty-six participants used
MapLens to play a location-based game in a city centre. Comparisons to a group
of 11 users with a standard 2D mobile map uncover phenomena that arise uniquely
when interacting with AR features in the wild. The main finding is that AR
features facilitate place-making by creating a constant need for referencing to
the physical, and in that it allows for ease of bodily configurations for the
group, encourages establishment of common ground, and thereby invites
discussion, negotiation and public problem-solving. The main potential of AR
maps lies in their use as a collaborative tool.

Going My Way is a mobile user-aware route planner. The system collects GPS
data of a user's everyday locations and provides directions from an
automatically selected set of landmarks that are close to the destination,
informed by the user's usual travel patterns. In this paper, we present a brief
description of the system, the results of a preliminary experiment in memory
and recognition of landmarks, in addition to the results of a user evaluation
of the system.

We investigate the prediction of player engagement to address temporal
issues arising from the long-term character of pervasive experiences such as
interruptibility, mutual player state awareness, disengagement and
synchronization on re-engagement. We introduce a model that operationalizes
engagement in terms of the elapsed and response time in game messages. We
designed and conducted an experiment based on the experience-sampling method to
evaluate our model on the basis of a long-term SMS-based game called Day of the
Figurines. Statistical analysis supports the hypothesis that player engagement
can be predicted by the continuous data properties elapsed time and response
time. Our findings point towards further research towards the adaptation of
pervasive experiences to the player's temporal context.

New mobile interactions

In this paper, we explore how to add pointing input capabilities to very
small screen devices. On first sight, touchscreens seem to allow for particular
compactness, because they integrate input and screen into the same physical
space. The opposite is true, however, because the user's fingers occlude
contents and prevent precision.
We argue that the key to touch-enabling very small devices is to use touch
on the device backside. In order to study this, we have created a 2.4"
prototype device; we simulate screens smaller than that by masking the screen.
We present a user study in which participants completed a pointing task
successfully across display sizes when using a back-of device interface. The
touchscreen-based control condition (enhanced with the shift technique), in
contrast, failed for screen diagonals below 1 inch. We present four form factor
concepts based on back-of-device interaction and provide design guidelines
extracted from a second user study.

The Codex is a dual-screen tablet computer, about the size of a 4"x 6 day
planner, with a self-supporting binding and embedded sensors. The device can be
oriented in a variety of postures to support different nuances of individual
work, ambient display, or collaboration with another user. In the context of a
pen-operated note taking application, we demonstrate interaction techniques
that support a fluid division of labor for tasks and information across the two
displays while minimizing disruption to the primary experience of authoring
notes.

Most studies on tilt based interaction can be classified as point-designs
that demonstrate the utility of wrist-tilt as an input medium; tilt parameters
are tailored to suit the specific interaction at hand. In this paper, we
systematically analyze the design space of wrist-based interactions and focus
on the level of control possible with the wrist. In a first study, we
investigate the various factors that can influence tilt control, separately
along the three axes of wrist movement: flexion/extension,
pronation/supination, and ulnar/radial deviation. Results show that users can
control comfortably at least 16 levels on the pronation/supination axis and
that using a quadratic mapping function for discretization of tilt space
significantly improves user performance across all tilt axes. We discuss the
findings of our results in the context of several interaction techniques and
identify several general design recommendations.

Designers of mobile, social systems must carefully think about how to help
their users manage spatial, semantic, and social modes of navigation. Here, we
describe our deployment of MobiTags, a system to help museum visitors interact
with a collection of "open storage" exhibits, those where the museum provides
little curatorial information. MobiTags integrates social tagging, art
information, and a map to support navigation and collaborative curation of
these open storage collections. We studied 23 people's use of MobiTags in a
local museum, combining interview data with device use logs and tracking of
people's movements to understand how MobiTags affected their navigation and
experience in the museum. Despite a lack of social cues, people feel a strong
sense of social presence -- and social pressure -- through seeing others' tags.
The tight coupling of tags, item information, and map features also supported a
rich set of practices around these modes of navigation.

Studies of interactive systems in museums have raised important design
considerations, but so far have failed to address sufficiently the
particularities of family interaction and co-operation. This paper introduces
qualitative video-based observations of Japanese families using an interactive
portable guide system in a museum. Results show how unexpected usage can occur
through particularities of interaction between family members. The paper
highlights the necessity to more fully consider familial relationships in HCI.

This paper presents the evolution of a tool to support the rapid prototyping
of hybrid museum experiences by domain professionals. The developed tool uses
visual markers to associate digital resources with physical artefacts. We
present the iterative development of the tool through a user centred design
process and demonstrate its use by domain experts to realise two distinct
hybrid exhibits. The process of design and refinement of the tool highlights
the need to adopt an experience oriented approach allowing authors to think in
terms of the physical and digital "things" that comprise a hybrid experience
rather than in terms of the underlying technical components.

Security and privacy

Backup authentication mechanisms help users who have forgotten their
passwords regain access to their accounts-or at least try. Today's systems fall
short in meeting both security and reliability requirements. We designed,
built, and tested a new backup authentication system that employs a
social-authentication mechanism. The system employs trustees previously
appointed by the account holder to verify the account holder's identity. We ran
three experiments to determine whether the system could (1) reliably
authenticate account holders, (2) resist email attacks that target trustees by
impersonating account holders, and (3) resist phone-based attacks from
individuals close to account holders. Results were encouraging: seventeen of
the nineteen participants who made the effort to call trustees authenticated
successfully. However, we also found that users must be reminded of who their
trustees are. While email-based attacks were largely unsuccessful, stronger
countermeasures will be required to counter highly-personalized phone-based
attacks.

Keywords: privacy, security, usability testing and evaluation

"When I am on Wi-Fi, I am fearless": privacy concerns & practices in
everyday Wi-Fi use

Increasingly, users access online services such as email, e-commerce, and
social networking sites via 802.11-based wireless networks. As they do so, they
expose a range of personal information such as their names, email addresses,
and ZIP codes to anyone within broadcast range of the network. This paper
presents results from an exploratory study that examined how users from the
general public understand Wi-Fi, what their concerns are related to Wi-Fi use,
and which practices they follow to counter perceived threats. Our results
reveal that while users understand the practical details of Wi-Fi use
reasonably well, they lack understanding of important privacy risks. In
addition, users employ incomplete protective practices which results in a false
sense of security and lack of concern while on Wi-Fi. Based on our results, we
outline opportunities for technology to help address these problems.

Keywords: Wi-Fi, privacy, security, user study, wireless networks

Who's viewed you?: the impact of feedback in a mobile location-sharing
application

Feedback is viewed as an essential element of ubiquitous computing systems
in the HCI literature for helping people manage their privacy. However, the
success of online social networks and existing commercial systems for mobile
location sharing which do not incorporate feedback would seem to call the
importance of feedback into question. We investigated this issue in the context
of a mobile location sharing system. Specifically, we report on the findings of
a field deployment of Locyoution, a mobile location sharing system. In our
study of 56 users, one group was given feedback in the form of a history of
location requests, and a second group was given no feedback at all. Our major
contribution has been to show that feedback is an important contributing factor
towards improving user comfort levels and allaying privacy concerns.
Participants' privacy concerns were reduced after using the mobile location
sharing system. Additionally, our study suggests that peer opinion and
technical savviness contribute most to whether or not participants thought they
would continue to use a mobile location technology.

Web searching and browsing

We present contextual facets, a novel user interface technique for
navigating websites that publish large collections of semi-structured data.
Contextual facets extend traditional faceted navigation techniques by
transforming webpage elements into user interface components for filtering and
retrieving related webpages. To investigate users' reactions to contextual
facets, we built FacetPatch, a web browser that automatically generates
contextual facet interfaces. As the user browses the web, FacetPatch
automatically extracts semi-structured data from collections of webpages and
overlays contextual facets on top of the current page. Participants in an
exploratory user evaluation of FacetPatch were enthusiastic about contextual
facets and often preferred them to an existing, familiar faceted navigation
interface. We discuss how we improved the design of contextual facets and
FacetPatch based on the results of this study.

People regularly interact with different representations of Web pages. A
person looking for new information may initially find a Web page represented as
a short snippet rendered by a search engine. When he wants to return to the
same page the next day, the page may instead be represented by a link in his
browser history. Previous research has explored how to best represent Web pages
in support of specific task types, but, as we find in this paper, consistency
in representation across tasks is also important. We explore how different
representations are used in a variety of contexts and present a compact
representation that supports both the identification of new, relevant Web pages
and the re-finding of previously viewed pages.

The act of encountering information unexpectedly has long been identified as
valuable, both as a joy in itself and as part of task-focused problem solving.
There has been a concern that highly accurate search engines and targeted
personalization may reduce opportunities for serendipity on the Web. We examine
whether there is the potential for serendipitous encounters during Web search,
and whether improving search relevance through personalization reduces this
potential. By studying Web search query logs and the results people judge
relevant and interesting, we find many of the queries people perform return
interesting (potentially serendipitous) results that are not directly relevant.
Rather than harming serendipity, personalization appears to identify
interesting results in addition to relevant ones.

Tag clouds have become a frequently used interaction technique in the web.
Recently several approaches to present tag clouds with the tags semantically
clustered have been proposed. However, it remains unclear whether the expected
gains in performance and advantages in interaction actually can be realized as
no empirical evaluations of such approaches are available yet. In this paper we
describe a series of experiments designed to evaluate the effects of semantic
versus alphabetical and random arrangements of tags in tag clouds. The results
of our work indicate that semantically clustered tag clouds can provide
improvements over random layouts in specific search tasks and that they tend to
increase the attention towards tags in small fonts compared to other layouts.
Also, semantically structured tag clouds were preferred by about half of the
users for general search tasks. Tag cloud layout does not seem to influence the
ability to remember tags.

Keywords: clustering, folksonomy, tag clouds, visualization

Hospitals

A mobile voice communication system in medical setting: love it or hate it?

Hospital work coordination and collaboration often requires mobility for
acquiring proper information and resources. In turn, the spatial distribution
and the mobility of clinicians can curtail the opportunities for effective
communications making collaboration difficult. In this situation, a mobile
hands-free voice communication system, Vocera, was introduced to enhance
communication. It supports quick and impromptu conversations among coworkers
for work coordination and collaboration anytime and anywhere. We study this
deployment and present our findings concerning the impact of this communication
system on the information flow. Our information flow framework's communication
strategies help contrast the information processes before and after the
deployment of Vocera.

Ethical requirements, severe constraints on access to end users and the
necessity of real-world clinical evaluations represent significant challenges
to designers of new technologies in mental healthcare (MHC) settings. This
paper describes the collaborative approaches, incorporating HCI methods with
input for MHC professionals and MHC theory, which were applied in the
development of Personal Investigator (PI), a 3D computer game developed to
support adolescent mental health interventions. Different stages in the
evaluation of PI are discussed and the lessons learned through a multi-site
clinical evaluation are presented. This evaluation has provided strong initial
evidence that games such as PI offer the potential to improve adolescent
engagement in talk-based interventions. It has also provided an insight into
factors which should be considered in future designs in the MHC domain, e.g.
the need to incorporate high levels of adaptability in future systems. Based on
the difficulties encountered and lessons learned critical aims for future
research are outlined.

We conducted a field-based study examining informal nursing information. We
examined the use of this information before and after the adoption of a CPOE
(Computerized Provider Order Entry) system in an inpatient unit of a large
teaching hospital. Before CPOE adoption, nurses used paper working documents to
detail psycho-social information about patients; after the CPOE adoption, they
did not use paper or digital notes as was planned. The paper describes this
process and analyses how several interlocked reasons contributed to the loss of
this information in written form. We found that a change in physical location,
sufficient convenience, visibility of the information, and permanency of
information account for some, but not all, of the outcome. As well, we found
that computerization of the nursing data led to a shift in the politics of the
information itself -- the nurses no longer had a cohesive agreement about the
kinds of data to enter into the system. The findings address the requirements
of healthcare computerization to support both formal and informal work
practices, respecting the nature of nursing work and the politics of
information inherent in complex medical work.

Social software in office

The attention economy motivates participation in peer-produced sites on the
Web like YouTube and Wikipedia. However, this economy appears to break down at
work. We studied a large internal corporate blogging community using log files
and interviews and found that employees expected to receive attention when they
contributed to blogs, but these expectations often went unmet. Like in the
external blogosphere, a few people received most of the attention, and many
people received little or none. Employees expressed frustration if they
invested time and received little or no perceived return on investment. While
many corporations are looking to adopt Web-based communication tools like
blogs, wikis, and forums, these efforts will fail unless employees are
motivated to participate and contribute content. We identify where the
attention economy breaks down in a corporate blog community and suggest
mechanisms for improvement.

In this paper, we focus on the role that photo viewing plays within a large
distributed enterprise. We describe the results of an analysis of users'
viewing behavior through log activity and semi-structured interviews with
respect to a photo sharing application embedded within an internal social
networking site. Specifically, we investigate how these forms of expression can
assist in the transmission of the norms and values associated with the culture
of the organization through impression formation. We conclude by discussing how
photos might act as a resource for newcomers to learn about the various aspects
of the organizational culture and offer design suggestions for photo viewing
systems within organizations.

Technology makes it possible to share many different types of information
with coworkers. We conducted a large-scale survey (N=549) to better understand
current sharing among coworkers, how people stay aware of collocated and remote
coworkers, and whether their willingness to share different types of awareness
information changes based on the location in which the information is
displayed. Contrary to our expectations, the display location did not greatly
affect what respondents were willing to share. Our results also suggest
considerations for researchers building situated displays, as respondents had
concerns about unintended viewers and encouraging people to visit their
personal space when they were not present.

Keywords: CSCW, awareness, privacy, situated display

Yours, mine and (not) ours: social influences on group information
repositories

Group information repositories are systems for storing and organizing files
in a central location all group members can access. The functionality and
capabilities of these systems are essentially the same as the desktop metaphor
of personal information management (PIM) systems. Using a case study of a group
information repository, I argue that social factors affect the information
structure of the repository, and how it grows and evolves over time. Users
restrict their activities to files they own, are reluctant to delete files that
might be useful to others, dislike the clutter that results, and can become
demotivated if no one views files they uploaded.

Studying intelligent systems

As computational agents become more sophisticated, it will frequently be
necessary for the agents to disagree with users. In these cases, it might be
useful for the agent to use politeness strategies that defuse the person's
frustrations and preserve the human-computer relationship. One such strategy is
distancing, which we implemented by spatially distancing an agent's voice from
its body. In a 2 (agent disagreement: none vs. some) x 2 (agent voice location:
on robotic body vs. in control box) between-participants experiment, we studied
the effects of agent disagreement and agent voice location in a collaborative
human-agent desert survival task (N=40). People changed their answers more
often when agents disagreed with them and felt more similar to agents that
always agreed with them, even when substantive content was identical.
Strikingly, people felt more positively toward the disagreeing agent whose
voice came from a separate control box rather than from its body; for
agreement, the body-attached voice was preferred.

Under certain conditions, we appear willing to see and interact with
computing machines as though they exhibited intelligence, at least an
intelligence of sorts. Using examples from AI and robotics research, as well as
a selection of relevant art installations and anthropological fieldwork, this
paper reflects on some of our interactions with the kinds of machines we seem
ready to treat as intelligent. Broadly, it is suggested that ordinary, everyday
ideas of intelligence are not fixed, but rather actively seen and enacted in
the world. As such, intelligence does not just belong to the province of the
human mind, but can emerge in quite different, unexpected forms in things. For
HCI, it is proposed this opens up a new set of possibilities for design;
examining the ways intelligence is seen and enacted gives rise to a very
different way of thinking about the intersection between human and machine, and
thus promotes some radically new types of interactions with computing machines.

Keywords: intelligence, intelligent machines

Why and why not explanations improve the intelligibility of context-aware
intelligent systems

Context-aware intelligent systems employ implicit inputs, and make decisions
based on complex rules and machine learning models that are rarely clear to
users. Such lack of system intelligibility can lead to loss of user trust,
satisfaction and acceptance of these systems. However, automatically providing
explanations about a system's decision process can help mitigate this problem.
In this paper we present results from a controlled study with over 200
participants in which the effectiveness of different types of explanations was
examined. Participants were shown examples of a system's operation along with
various automatically generated explanations, and then tested on their
understanding of the system. We show, for example, that explanations describing
why the system behaved a certain way resulted in better understanding and
stronger feelings of trust. Explanations describing why the system did not
behave a certain way, resulted in lower understanding yet adequate performance.
We discuss implications for the use of our findings in real-world context-aware
applications.

Keywords: context-aware, explanations, intelligibility

Tabletops and single display groupware

An evaluation of coordination techniques for protecting objects and
territories in tabletop groupware

Indirect input techniques allow users to quickly access all parts of
tabletop workspaces without the need for physical access; however, indirect
techniques restrict the available social cues that are seen on direct touch
tables. This reduced awareness results in impoverished coordination; for
example, the number of conflicts might increase since users are more likely to
interact with objects that another person is planning to use. Conflicts may
also arise because indirect techniques reduce territorial behavior, expanding
the interaction space of each collaborator. In this paper, we introduce three
new tabletop coordination techniques designed to reduce conflicts arising from
indirect input, while still allowing users the flexibility of distant object
control. Two techniques were designed to promote territoriality and to allow
users to protect objects when they work near their personal areas, and the
third technique lets users set their protection levels dynamically. We present
the results of an evaluation, which shows that people prefer techniques that
automatically provide protection for personal territories, and that these
techniques also increase territorial behavior.

There is growing interest in tabletop interfaces that enable remote
collaboration by providing shared workspaces. This approach assumes that these
remote tabletops afford the same beneficial work practices as co-located
tabletop interfaces and traditional tables. This assumption has not been tested
in practice. We explore two such work practices in remote tabletop
collaboration: (a) coordination by territorial partitioning of space; and (b)
transitioning between individual and group work within a shared task. We have
evaluated co-located and remote tabletop collaboration. We found that remote
collaborators did not coordinate territorially as co-located collaborators did.
We found no differences between remote and co-located interfaces in their
ability to afford individual and group work. However, certain interaction
techniques impaired the ability to transition fluidly between these working
styles. We discuss causes and the implications for the design and future study
of these interfaces.

Tabletop and tangible interfaces are often described in terms of their
support for shared access to digital resources. However, it is not always the
case that collaborators want to share and help one another. In this paper we
detail a video-analysis of a series of prototyping sessions with children who
used both cardboard objects and an interactive tabletop surface. We show how
the material qualities of the digital interface and physical objects affect the
kinds of bodily strategies adopted by children to stop others from accessing
them. We discuss how children fight for and maintain control of physical versus
digital objects in terms of embodied interaction and what this means when
designing collaborative applications for shareable interfaces.

Keywords: children, collaboration, embodied interaction

Measuring the impact of third place attachment on the adoption of a
place-based community technology

CoCollage is a placed-based community technology that leverages the power of
online social networking to facilitate awareness and face-to-face interactions
in a third place. We adapted standardized measures of place attachment, social
networks and psychological sense of community to provide a framework grounded
in the social science literature for studying real world adoption of
place-based community technologies. We found the standardized measures of place
attachment and psychological sense of community meaningfully predicted
likelihood of technology adoption and usage in a café. We discuss some
lessons learned from our initial deployment of CoCollage in a real-world
setting to support a nascent place-based community.

Systems for children

Mischief is a system for classroom interaction that allows multiple children
to use individual mice and cursors to interact with a single large display
[20]. While the system can support large groups of children, it is unclear how
children's performance is affected as group size increases. We explore this
question via a study involving two tasks, with children working in group sizes
ranging from 1 to 32. The first required reciprocal selection of two on-screen
targets, resembling a swarm pointing scenario that might be used in educational
applications. The second, a more temporally and spatially distributed pointing
task, had children entering different words by selecting characters on an
on-screen keyboard. Results indicate that performance is significantly affected
by group size only when targets are small. Further, group size had a smaller
effect when pointing was spatially and temporally distributed than when
everyone was concurrently aiming at the same targets.

At first blush, mobile media may appear a promising solution to the problem
arising from the fact that parents in the present-day kindergarten institution
rely almost solely on teachers' retrospective reports on their child's daily
activities. However, a kindergarten is a delicate social fabric that mixes
professional roles (the teachers') with socio-emotional relationships
(parenting and caring) and involves stakeholders who are dependent on adults in
the use of technology (the children). To date, no studies have been reported
that critically examine the boundary conditions for successful mobile media
applications in such settings. We present a study of Meaning, a one-button
capture-and-push-to-Web solution that was used by a Finnish kindergarten for a
month. Interviews and the amount of media sent suggest that the intervention
was a success, and we report on seven uses of media. However, all uses were
critically affected by the users' social fabric, in which the teachers were the
nexus. We conclude by discussing various ways in which the heterogeneity of the
user group affected mobile media use.

Children with severe motor impairments such as with disabilities resulting
from severe cerebral palsy benefit greatly from assistive technology, but very
little guidance is available on how to collaborate with this population as
partners in the design of such technology. To explore how to facilitate such
collaborations, a field-based participant observation study, as well as
structured and unstructured interviews, were conducted at a home for children
with severe disabilities. Team-building collaborative design activities were
pursued. Guidelines are proposed for how to collaborate with children with
severe motor impairments.

This paper reports the design of a pervasive game for children to
demonstrate the design vision of Head-Up games, a genre of pervasive games that
puts outdoors play center stage, combining the benefits of traditional outdoor
games with the opportunities for richer experiences and innovation offered by
new media. The design of the game, called HeartBeat, explores the use of
physiological sensing and more specifically heart rate measurement as input to
the game and as an approach to enhance the pervasive gaming experience.
Evaluation with 32 children outdoors showed how the game promotes physical
activity and social interaction between children in ways one would expect from
traditional outdoor games.

A well designed user interface (UI) should be transparent, allowing users to
focus their mental workload on the task at hand. We hypothesize that the
overall mental workload required to perform a task using a computer system is
composed of a portion attributable to the difficulty of the underlying task
plus a portion attributable to the complexity of operating the user interface.
In this regard, we follow Shneiderman's theory of syntactic and semantic
components of a UI. We present an experiment protocol that can be used to
measure the workload experienced by users in their various cognitive resources
while working with a computer. We then describe an experiment where we used the
protocol to quantify the syntactic workload of two user interfaces. We use
functional near infrared spectroscopy, a new brain imaging technology that is
beginning to be used in HCI. We also discuss extensions of our techniques to
adaptive interfaces.

One of the major challenges of video game design is to have appropriate
difficulty levels for users in order to maximize the entertainment value of the
game. Game players may lose interests if a game is either too easy or too
difficult. This paper presents a novel methodology to improve user's experience
in computer games by automatically adjusting the level of the game difficulty.
The difficulty level is computed from measurements of the facial physiology of
the players at a distance. The measurements are based on the assumption that
the players' performance during the game-playing session alters blood flow in
the supraorbital region, which is an indirect measurement of increased mental
activities. This alters heat dissipation, which can be monitored in a
contact-free manner through a thermal imaging-based stress monitoring and
analysis system, known as StressCam.
In this work, we investigated on two primary objectives: (1) the feasibility
of utilizing the facial physiology in automatically adjusting the difficulty
level of the game and (2) the capability of the automatic difficulty level
adjustment in improving game players' experience. We employed and extended a
XNA video game for this study, and performed an in-depth, comparative usability
evaluation on it. Our results show that the automatic difficulty adjustable
system successfully maintains game players' interests and substantially
outperforms traditional fixed-difficulty mode games. Although a number of
issues of this preliminary study remain to be investigated further, this
research opens a new direction that utilizes non-contact stress measurements
for monitoring and further enhancing a variety of user-centric, interactive
entertainment activities.

In this paper, we propose a model to predict the performance of selection
techniques using Brain-Computer Interfaces based on P300 signals. This model is
based on Markov theory and can compute both the time required to select a
target and the number of visual flashes needed. We illustrate how to use this
model with three different interaction techniques to select a target. A first
experimental evaluation with three healthy participants shows a good match
between the model and the experimental data.

The overwhelming amount of information on the web makes it critical for
users to quickly and accurately evaluate the relevance of content. Here we
tested whether pupil size can be used to discriminate the perceived relevance
of web search results. Our findings revealed that measures of pupil size carry
information that can be used to discriminate the relevance of text and image
web search results, but the low signal-to-noise ratio poses challenges that
need to be overcome when using this technique in naturalistic settings. Despite
these challenges, our findings highlight the promise that pupillometry has as a
technique that can be used to assess interest and relevance in web interaction
in a non-intrusive and objective way.

Keywords: pupil dilation, relevance, web search results

Reflecting on design

Anatomy of a failure: how we knew when our design went wrong, and what we
learned from it

In this paper, we describe the failure of a novel sensor-based system
intended to evoke user interpretation and appropriation in domestic settings.
We contrast participants' interactions in this case study with those observed
during more successful deployments to identify 'symptoms of failure' under four
themes: engagement, reference, accommodation, and surprise and insight. These
themes provide a set of sensitivities or orientations that may complement
traditional task-based approaches to evaluation as well as the more open-ended
ones we describe here. Our system showed symptoms of failure under each of
these themes. We examine the reasons for this at three levels: problems
particular to the specific design hypothesis; problems relevant for
input-output mapping more generally; and problems in the design process we
used. We conclude by noting that, although interpretive systems such as the one
we describe here may succeed in a myriad of different ways, it is reassuring to
know that they can also fail, and fail incontrovertibly, yet instructively.

Principled knowledge is a mark of any established disciplinary practice. Its
derivation and validation of varies across disciplines, but HCI has tended
towards posthoc ('a posteriori') syntheses. We present an alternative a priori
approach that is relatively compact and open to inspection. We use John
Heskett's position on the origins of design outcomes to derive six
metaprinciples for all design processes: receptiveness, expressivity,
committedness, credibility, inclusiveness and improvability. Although very
abstract, these meta-principles generate critical insights into existing HCI
approaches, identifying gaps in suitability and coverage. Practical value is
increased by progressive instantiation of meta-principles to create first
craft-specific, and ultimately project-specific, Interaction Design principles.
A worth-centred approach is adopted to illustrate progressive instantiation
towards a framework of adapted and novel HCI approaches. The internal coherence
of the six metaprinciples is shown to provide direct effective support for
synergistic progressive instantiation.

In this paper, we argue that HCI practitioners are facing new challenges in
design and evaluation that can benefit from the establishment of commonly
valued use qualities, with associated strategies for producing and rigorously
evaluating work. We present a particular use quality 'suppleness' as an
example. We describe ways that use qualities can help shape design and
evaluation process, and propose tactics for the CHI community to use to
encourage the evolution of bodies of knowledge around use qualities.

Tactile UI

While learning new motor skills, we often rely on feedback from a trainer.
Auditive feedback and demonstrations are used most frequently, but in many
domains they are inappropriate or impractical. We introduce tactile
instructions as an alternative to assist in correcting wrong posture during
physical activities, and present a set of full-body vibrotactile patterns. An
initial study informed the design of our tactile patterns, and determined
appropriate locations for feedback on the body. A second experiment showed that
users perceived and correctly classified our tactile instruction patterns in a
relaxed setting and during a cognitively and physically demanding task. In a
final experiment, snowboarders on the slope compared their perception of
tactile instructions with audio instructions under real-world conditions.
Tactile instructions achieved overall high recognition accuracy similar to
audio instructions. Moreover, participants responded quicker to instructions
delivered over the tactile channel than to instructions presented over the
audio channel. Our findings suggest that these full-body tactile feedback
patterns can replace audio instructions during physical activities.

When designing interfaces for mobile devices it is important to take into
account the variety of contexts of use. We present a study that examines how
changing noise and disturbance in the environment affects user performance in a
touchscreen typing task with the interface being presented through visual only,
visual and tactile, or visual and audio feedback. The aim of the study is to
show at what exact environmental levels audio or tactile feedback become
ineffective. The results show significant decreases in performance for audio
feedback at levels of 94dB and above as well as decreases in performance for
tactile feedback at vibration levels of 9.18g/s. These results suggest that at
these levels, feedback should be presented by a different modality. These
findings will allow designers to take advantage of sensor enabled mobile
devices to adapt the provided feedback to the user's current context.

Predictive text entry provides a fast way to enter text on phones and other
small devices. Early work on predictive text entry highlighted that the
reaction time for checking the screen dominates text entry times. Improving
accuracy of predictions brings a downside: as prediction gets better, users
will drop the slow operation of checking the screen and will thus miss
prediction errors and system feedback/suggestions. In this note, we present an
experiment into the use of vibration to alert the user when word completion is
likely to aid them, using a dynamic approach based on their current typing
speed, and when there are no dictionary matches to their entry. Results show
significantly faster entry rates for users with vibration alerts, raising
speeds from 20wpm to 23wpm once practiced.

In this paper, we consider a passive approach to tactile presentation based
on changing the surface textures of objects that might naturally be handled by
a user. This may allow devices and other objects to convey small amounts of
information in very unobtrusive ways and with little attention demand. This
paper considers several possible uses for this style of display and explores
implementation issues. We conclude with results from our user study, which
indicate that users can detect upwards of four textural states accurately with
even simple materials.

TypeRight is a new tactile input device for text entry. It combines the
advantages of tactile feedback with error prevention methods of word
processors. TypeRight extends the standard keyboard so that the resistance to
press each key becomes dynamically adjustable through software. Before each
keystroke, the resistance of keys that would lead to a typing error according
to dictionary and grammar rules is increased momentarily to make them harder to
press, thus avoiding typing errors rather than indicating them after the fact.
Two user studies showed that TypeRight decreases error correction rates by an
average of 46%.

Gesture UIs

GestureBar is a novel, approachable UI for learning gestural interactions
that enables a walk-up-and-use experience which is in the same class as
standard menu and toolbar interfaces. GestureBar leverages the familiar, clean
look of a common toolbar, but in place of executing commands, richly discloses
how to execute commands with gestures, through animated images, detail tips and
an out-of-document practice area. GestureBar's simple design is also general
enough for use with any recognition technique and for integration with
standard, non-gestural UI components. We evaluate GestureBar in a formal
experiment showing that users can perform complex, ecologically valid tasks in
a purely gestural system without training, introduction, or prior gesture
experience when using GestureBar, discovering and learning a high percentage of
the gestures needed to perform the tasks optimally, and significantly
outperforming a state of the art crib sheet. The relative contribution of the
major design elements of GestureBar is also explored. A second experiment shows
that GestureBar is preferred to a basic crib sheet and two enhanced crib sheet
variations.

Keywords: approachability, disclosure, gestures, learning, pen

Lean collaboration through video gestures: co-ordinating the production of
live televised sport

This paper examines the work and interactions between camera operators and a
vision mixer during an ice hockey match, and presents an interaction analysis
using video data. We analyze video-mediated indexical gestures in the
collaborative production of live sport on television between distributed team
members. The findings demonstrate how video forms the topic, resource and
product of collaboration: whilst it shapes the nature of the work (editing), it
is simultaneously also the primary resource for supporting mutual orientation
and negotiating shot transitions between remote participants (coordination), as
well as its end product (broadcast). Our analysis of current professional
activities is used to develop implications for the design of future services
for live collaborative video production.

This paper investigates using stroke gestures as shortcuts to menu
selection. We first experimentally measured the performance and ease of
learning of stroke shortcuts in comparison to keyboard shortcuts when there is
no mnemonic link between the shortcut and the command. While both types of
shortcuts had the same level of performance with enough practice, stroke
shortcuts had substantial cognitive advantages in learning and recall. With the
same amount of practice, users could successfully recall more shortcuts and
make fewer errors with stroke shortcuts than with keyboard shortcuts. The
second half of the paper focuses on UI development support and articulates
guidelines for toolkits to implement stroke shortcuts in a wide range of
software applications. We illustrate how to apply these guidelines by
introducing the Stroke Shortcuts Toolkit (SST) which is a library for adding
stroke shortcuts to Java Swing applications with just a few lines of code.

Keywords: gesture, shortcuts, stroke, toolkit

Understanding graphs

Graphs are often visualized using node-link representations: vertices are
depicted as dots, edges are depicted as (poly)lines connecting two vertices. A
directed edge running from vertex A to B is generally visualized using an arrow
representation: a (poly)line with a triangular arrowhead at vertex B. Although
this representation is intuitive, it is not guaranteed that a user is able to
determine edge direction as quickly and unambiguously as possible; alternative
representations that exhibit less occlusion and visual clutter might be better
suited. To investigate this, we developed five additional directed-edge
representations using combinations of shape and color. We performed a user
study in which subjects performed different tasks on a collection of graphs
using these representations and combinations thereof to investigate which
representation is best in terms of speed and accuracy. We present our initial
hypotheses, the outcome of the user studies, and recommendations regarding
directed-edge visualization.

Many online mapping applications let users define routes, perhaps for
sharing a favorite bicycle commuting route or rating several contiguous city
blocks. At the UI level, defining a route amounts to selecting a fairly large
number of objects -- the individual segments of roads and trails that make up
the route. We present a novel interaction technique for this task called path
selection. We implemented the technique and evaluated it experimentally,
finding that adding path selection to a state-of-the-art technique for
selecting individual objects reduced route definition time by about a factor of
2, reduced errors, and improved user satisfaction. Detailed analysis of the
results showed path selection is most advantageous (a) for routes with long
straight segments and (b) when objects that are optimal click targets also are
visually attractive.

Applications supporting navigation in large networks are used every days by
millions of people. They include road map navigators, flight route
visualization systems, and network visualization systems using node-link
diagrams. These applications currently provide generic interaction methods for
navigation: pan-and-zoom and sometimes bird's eye views.
This article explores the idea of exploiting the connection information
provided by the network to help navigate these large spaces. We visually
augment two traditional navigation methods, and develop two special-purpose
techniques. The first new technique, called "Link Sliding", provides guided
panning when continuously dragging along a visible link. The second technique,
called "Bring & Go", brings adjacent nodes nearby when pointing to a node. We
compare the performance of these techniques in both an adjacency exploration
task and a node revisiting task. This comparison illustrates the various
advantages of content-aware network navigation techniques. A significant speed
advantage is found for the Bring & Go technique over other methods.

Computer mediated communication 2

Many couples are forced to live apart, for work, school or other reasons.
This paper describes our study of 13 such couples and what they lack from
existing communication technologies. We explored what they wanted to share
(presence, mood, environment, daily events and activities), how they wanted to
share (simple, lightweight, playful, pleasant interaction), and when they
wanted to share ('empty moments' such as waiting, walking, taking a break,
waking up, eating, and going to sleep). 'Empty moments' provide a compelling
new opportunity for design, requiring subtlety and flexibility to enable
participants to share connection without explicit messages. We designed MissU
as a technology probe to study empty moments in situ. Similar to a private
radio station, MissU shares music and background sounds. Field studies produced
results relevant to social science, technology and design: couples with
established routines were comforted; characteristics such as ambiguity and
'movable' technology (situated in the home yet portable) provide support. These
insights suggest a design space for supporting the sharing of empty moments.

We build on our prior work with computer-supported teams performing a
complex decision-making task on maps, where the distinction between content and
process common ground is proposed. In this paper we describe a distributed
geo-collaboration software prototype. The system design rationale was gleaned
from fieldwork, literature on team cognition, and an earlier lab study
introducing a reference task with face-to-face teams. We report on a controlled
experiment that evaluates this design rationale. Distinct sets of measures show
that the prototype supported both content and process common ground, offsetting
the costs imposed by the distributed setting. We interpret the results in
relation to prior work on common ground and draw implications for moving beyond
current models of sharing and coordination.

Conversation Clusters explores the use of visualization to highlight salient
moments of live conversation while archiving a meeting. Cheaper storage and
easy access to recording devices allows extensive archival. However, as the
size of the archive grows, retrieving the desired moments becomes increasingly
difficult. We approach this problem from a socio-technical perspective and
utilize human intuition aided by computer memory. We present computationally
detected topics of conversation as visual summaries of discussion and as
reference points into the archive. To further bootstrap the system, humans can
participate in a dialog with the visualization of the clustering process and
shape the development of clustering models.

We performed an empirical study to understand the relative contributions of
real-time transcription to a non-native speaker's comprehension in audio/video
meetings. 48 participants were assigned to 2 presentation modes (audio,
audio+video) and 3 transcription modes (no transcript, real-time transcripts in
the streaming mode, transcripts with all past records) in a 3x2 factorial
experimental design. The results suggest that comprehension can be
significantly improved for both audio and audio+video conditions when real-time
transcription is provided. Also, the participants reported positive subjective
responses to the presence of real-time transcription in terms of usefulness,
preference, and willingness to use such a feature if provided. No cognitive
load issues were reported by the participants in the ability to synthesize
across modalities. Implications for system development and design, as well as
future work utilizing automation speech recognition to provide the transcripts
are discussed.

Informed design

As HCI becomes more self-consciously implicated in culture, theories from
cultural studies, in particular aesthetics and critical theory, are
increasingly working their way into the field. However, the use of aesthetics
and critical theory in HCI remains both marginal and uneven in quality. This
paper explores the state of the art of aesthetics and critical theory in the
field, before going on to explore the role of these cultural theories in the
analysis and deployment of the twin anchors of interaction: the user and the
artifact. In concludes with a proposed mapping of aesthetics and critical
theory into interaction design, both as a practice and as a discipline.

Prior knowledge is a critical resource for design, especially when designers
are striving to generate new ideas for complex problems. Systems that improve
access to relevant prior knowledge and promote reuse can improve design
efficiency and outcomes. Unfortunately, such systems have not been widely
adopted indicating that user needs in this area have not been adequately
understood. In this paper, we report the results of a contextual inquiry into
the practices of and attitudes toward knowledge management and reuse during
early design. The study consisted of interviews and surveys with professional
designers in the creative domains. A novel aspect of our work is the focus on
early design, which differs from but complements prior works' focus on
knowledge reuse during later design and implementation phases. Our study
yielded new findings and implications that, if applied, will help bring the
benefits of knowledge management systems and reuse into early design activity.